Allow boards to provide their own function for reading the timer IRQ number

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>

--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -47,6 +47,7 @@
 #include <asm/mmu_context.h>
 #include <asm/types.h>
 #include <asm/stacktrace.h>
+#include <asm/time.h>
 
 extern void check_wait(void);
 extern asmlinkage void r4k_wait(void);
@@ -1514,6 +1515,8 @@ void __cpuinit per_cpu_trap_init(void)
 	 */
 	if (cpu_has_mips_r2) {
 		cp0_compare_irq = (read_c0_intctl() >> 29) & 7;
+		if (get_c0_compare_irq)
+			cp0_compare_irq = get_c0_compare_irq();
 		cp0_perfcount_irq = (read_c0_intctl() >> 26) & 7;
 		if (cp0_perfcount_irq == cp0_compare_irq)
 			cp0_perfcount_irq = -1;
--- a/arch/mips/include/asm/time.h
+++ b/arch/mips/include/asm/time.h
@@ -53,6 +53,7 @@ extern int (*perf_irq)(void);
 #ifdef CONFIG_CEVT_R4K
 extern int mips_clockevent_init(void);
 extern unsigned int __weak get_c0_compare_int(void);
+extern unsigned int __weak get_c0_compare_irq(void);
 #else
 static inline int mips_clockevent_init(void)
 {
