[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/sam/3n/irq.json

@@ -0,0 +1,39 @@
+{
+    "irqs": [
+        "supc", 
+        "rstc", 
+        "rtc", 
+        "rtt", 
+        "wdg", 
+        "pmc", 
+        "eefc0", 
+        "reserved0", 
+        "uart0", 
+        "uart1", 
+        "reserved1", 
+        "pioa", 
+        "piob", 
+        "pioc", 
+        "usart0", 
+        "usart1", 
+        "reserved2", 
+        "reserved3", 
+        "reserved4", 
+        "twi0", 
+        "twi1", 
+        "spi", 
+        "reserved5", 
+        "tc0", 
+        "tc1", 
+        "tc2", 
+        "tc3", 
+        "tc4", 
+        "tc5", 
+        "adc", 
+        "dacc", 
+        "pwm"
+    ], 
+    "partname_humanreadable": "Atmel SAM3N series", 
+    "partname_doxygen": "SAM3N", 
+    "includeguard": "LIBOPENCM3_SAM3N_NVIC_H"
+}

include/libopencm3/sam/3n/irq.yaml

@@ -1,36 +0,0 @@
-includeguard: LIBOPENCM3_SAM3N_NVIC_H
-partname_humanreadable: Atmel SAM3N series
-partname_doxygen: SAM3N
-irqs:
-  - supc
-  - rstc
-  - rtc
-  - rtt
-  - wdg
-  - pmc
-  - eefc0
-  - reserved0
-  - uart0
-  - uart1
-  - reserved1
-  - pioa
-  - piob
-  - pioc
-  - usart0
-  - usart1
-  - reserved2
-  - reserved3
-  - reserved4
-  - twi0
-  - twi1
-  - spi
-  - reserved5
-  - tc0
-  - tc1
-  - tc2
-  - tc3
-  - tc4
-  - tc5
-  - adc
-  - dacc
-  - pwm

include/libopencm3/sam/3x/irq.json

@@ -0,0 +1,52 @@
+{
+    "irqs": [
+        "supc", 
+        "rstc", 
+        "rtc", 
+        "rtt", 
+        "wdg", 
+        "pmc", 
+        "eefc0", 
+        "eefc1", 
+        "uart", 
+        "smc_sdramc", 
+        "sdramc", 
+        "pioa", 
+        "piob", 
+        "pioc", 
+        "piod", 
+        "pioe", 
+        "piof", 
+        "usart0", 
+        "usart1", 
+        "usart2", 
+        "usart3", 
+        "hsmci", 
+        "twi0", 
+        "twi1", 
+        "spi0", 
+        "spi1", 
+        "ssc", 
+        "tc0", 
+        "tc1", 
+        "tc2", 
+        "tc3", 
+        "tc4", 
+        "tc5", 
+        "tc6", 
+        "tc7", 
+        "tc8", 
+        "pwm", 
+        "adc", 
+        "dacc", 
+        "dmac", 
+        "uotghs", 
+        "trng", 
+        "emac", 
+        "can0", 
+        "can1"
+    ], 
+    "partname_humanreadable": "Atmel SAM3X series", 
+    "partname_doxygen": "SAM3X", 
+    "includeguard": "LIBOPENCM3_SAM3X_NVIC_H"
+}

include/libopencm3/sam/3x/irq.yaml

@@ -1,49 +0,0 @@
-includeguard: LIBOPENCM3_SAM3X_NVIC_H
-partname_humanreadable: Atmel SAM3X series
-partname_doxygen: SAM3X
-irqs:
-  - supc
-  - rstc
-  - rtc
-  - rtt
-  - wdg
-  - pmc
-  - eefc0
-  - eefc1
-  - uart
-  - smc_sdramc
-  - sdramc
-  - pioa
-  - piob
-  - pioc
-  - piod
-  - pioe
-  - piof
-  - usart0
-  - usart1
-  - usart2
-  - usart3
-  - hsmci
-  - twi0
-  - twi1
-  - spi0
-  - spi1
-  - ssc
-  - tc0
-  - tc1
-  - tc2
-  - tc3
-  - tc4
-  - tc5
-  - tc6
-  - tc7
-  - tc8
-  - pwm
-  - adc
-  - dacc
-  - dmac
-  - uotghs
-  - trng
-  - emac
-  - can0
-  - can1