[build] Remove PyYAML dependency

This converts all the YAML files to JSON files, as json parsing is built
into python instead of being a separate library requiring installation.

YAML is a superset of JSON, but putting comments in is not quite as obvious
as it is in yaml.

The following glue was used to convert yaml to json:
python -c 'import sys, yaml, json; json.dump(yaml.load(sys.stdin), sys.stdout, indent=4)' < $1 > $2

Clearly I haven't tested this on every single platform, and this
doesn't address the large blobs of yaml in the lpc4300 scripts directory,
only the cortex NVIC generation process.

I've tested a few IRQ driven example apps, and I've checked the generated
output of some known cases like the LM3s that has explicit gaps, and they are
all generated correctly.

include/libopencm3/lpc43xx/m0/irq.json

@@ -0,0 +1,36 @@
+{
+    "irqs": {
+        "0": "rtc", 
+        "1": "m4core", 
+        "2": "dma", 
+        "4": "flasheepromat", 
+        "5": "ethernet", 
+        "6": "sdio", 
+        "7": "lcd", 
+        "8": "usb0", 
+        "9": "usb1", 
+        "10": "sct", 
+        "11": "ritimer_or_wwdt", 
+        "12": "timer0", 
+        "13": "gint1", 
+        "14": "pin_int4", 
+        "15": "timer3", 
+        "16": "mcpwm", 
+        "17": "adc0", 
+        "18": "i2c0_or_irc1", 
+        "19": "sgpio", 
+        "20": "spi_or_dac", 
+        "21": "adc1", 
+        "22": "ssp0_or_ssp1", 
+        "23": "eventrouter", 
+        "24": "usart0", 
+        "25": "uart1", 
+        "26": "usart2_or_c_can1", 
+        "27": "usart3", 
+        "28": "i2s0_or_i2s1", 
+        "29": "c_can0"
+    }, 
+    "partname_humanreadable": "LPC 43xx series M0 core", 
+    "partname_doxygen": "LPC43xx (M0)", 
+    "includeguard": "LIBOPENCM3_LPC43xx_M0_NVIC_H"
+}

include/libopencm3/lpc43xx/m0/irq.yaml

@@ -1,34 +0,0 @@
-includeguard: LIBOPENCM3_LPC43xx_M0_NVIC_H
-partname_humanreadable: LPC 43xx series M0 core
-partname_doxygen: LPC43xx (M0)
-irqs:
-  0: rtc
-  1: m4core
-  2: dma
-# reserved: 3
-  4: flasheepromat
-  5: ethernet
-  6: sdio
-  7: lcd
-  8: usb0
-  9: usb1
-  10: sct
-  11: ritimer_or_wwdt
-  12: timer0
-  13: gint1
-  14: pin_int4
-  15: timer3
-  16: mcpwm
-  17: adc0
-  18: i2c0_or_irc1
-  19: sgpio
-  20: spi_or_dac
-  21: adc1
-  22: ssp0_or_ssp1
-  23: eventrouter
-  24: usart0
-  25: uart1
-  26: usart2_or_c_can1
-  27: usart3
-  28: i2s0_or_i2s1
-  29: c_can0

include/libopencm3/lpc43xx/m4/irq.json

@@ -0,0 +1,54 @@
+{
+    "irqs": {
+        "0": "dac", 
+        "1": "m0core", 
+        "2": "dma", 
+        "5": "ethernet", 
+        "6": "sdio", 
+        "7": "lcd", 
+        "8": "usb0", 
+        "9": "usb1", 
+        "10": "sct", 
+        "11": "ritimer", 
+        "12": "timer0", 
+        "13": "timer1", 
+        "14": "timer2", 
+        "15": "timer3", 
+        "16": "mcpwm", 
+        "17": "adc0", 
+        "18": "i2c0", 
+        "19": "i2c1", 
+        "20": "spi", 
+        "21": "adc1", 
+        "22": "ssp0", 
+        "23": "ssp1", 
+        "24": "usart0", 
+        "25": "uart1", 
+        "26": "usart2", 
+        "27": "usart3", 
+        "28": "i2s0", 
+        "29": "i2s1", 
+        "30": "spifi", 
+        "31": "sgpio", 
+        "32": "pin_int0", 
+        "33": "pin_int1", 
+        "34": "pin_int2", 
+        "35": "pin_int3", 
+        "36": "pin_int4", 
+        "37": "pin_int5", 
+        "38": "pin_int6", 
+        "39": "pin_int7", 
+        "40": "gint0", 
+        "41": "gint1", 
+        "42": "eventrouter", 
+        "43": "c_can1", 
+        "46": "atimer", 
+        "47": "rtc", 
+        "49": "wwdt", 
+        "51": "c_can0", 
+        "52": "qei"
+    }, 
+    "partname_humanreadable": "LPC 43xx series M4 core", 
+    "partname_doxygen": "LPC43xx (M4)", 
+    "includeguard": "LIBOPENCM3_LPC43xx_M4_NVIC_H"
+}

include/libopencm3/lpc43xx/m4/irq.yaml

@@ -1,55 +0,0 @@
-includeguard: LIBOPENCM3_LPC43xx_M4_NVIC_H
-partname_humanreadable: LPC 43xx series M4 core
-partname_doxygen: LPC43xx (M4)
-irqs:
-  0: dac           
-  1: m0core        
-  2: dma           
-# reserved: 3, 4
-  5: ethernet      
-  6: sdio          
-  7: lcd           
-  8: usb0          
-  9: usb1          
-  10: sct          
-  11: ritimer      
-  12: timer0       
-  13: timer1       
-  14: timer2       
-  15: timer3       
-  16: mcpwm        
-  17: adc0         
-  18: i2c0         
-  19: i2c1         
-  20: spi          
-  21: adc1         
-  22: ssp0         
-  23: ssp1         
-  24: usart0       
-  25: uart1        
-  26: usart2       
-  27: usart3       
-  28: i2s0         
-  29: i2s1         
-  30: spifi        
-  31: sgpio        
-  32: pin_int0     
-  33: pin_int1     
-  34: pin_int2     
-  35: pin_int3     
-  36: pin_int4     
-  37: pin_int5     
-  38: pin_int6     
-  39: pin_int7     
-  40: gint0        
-  41: gint1        
-  42: eventrouter  
-  43: c_can1       
-# reserved: 44, 45
-  46: atimer       
-  47: rtc          
-# reserved: 48
-  49: wwdt         
-# reserved: 50
-  51: c_can0       
-  52: qei