Remove WEAK from handler prototypes

These prototypes affect functions defined by application code.  Only
the implementations in libopencm3 are supposed to be weak; the
functions in application code should definitely not be.  Otherwise,
you'll end up with two weak symbols being linked together, and
it's luck as to which one the linker picks.

scripts/irq2nvic_h

@@ -121,7 +121,7 @@ def convert(infile, outfile_nvic, outfile_vectornvic, outfile_cmsis):
         data['irqcount'] = max([int(x) for x in data['irqs'].keys()]) + 1
 
     data['irqdefinitions'] = "\n".join('#define NVIC_%s_IRQ %d'%(v.upper(),int(k)) for (k,v) in irq2name)
-    data['isrprototypes'] = "\n".join('void WEAK %s_isr(void);'%name.lower() for name in irqnames)
+    data['isrprototypes'] = "\n".join('void %s_isr(void);'%name.lower() for name in irqnames)
     data['isrpragmas'] = "\n".join('#pragma weak %s_isr = blocking_handler'%name.lower() for name in irqnames)
     data['vectortableinitialization'] = ', \\\n    '.join('[NVIC_%s_IRQ] = %s_isr'%(name.upper(), name.lower()) for name in irqnames)
     data['cmsisbends'] = "\n".join("#define %s_IRQHandler %s_isr"%(name.upper(), name.lower()) for name in irqnames)