sh: Kill off unused SH-5 irq_describe cruft.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/include/cpu-sh5/cpu/irq.h

@@ -111,7 +111,6 @@
 #define TOP_PRIORITY	15
 
 extern int intc_evt_to_irq[(0xE20/0x20)+1];
-int intc_irq_describe(char* p, int irq);
 extern int platform_int_priority[NR_INTC_IRQS];
 
 #endif /* __ASM_SH_CPU_SH5_IRQ_H */