ARM: perf: move CPU-specific PMU handling code into separate file

This patch moves the CPU-specific PMU handling code out of perf_event.c
and into perf_event_cpu.c.

Signed-off-by: Will Deacon <will.deacon@arm.com>
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index cfbe3b4..1c43214 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -69,7 +69,7 @@
 obj-$(CONFIG_CPU_MOHAWK)	+= xscale-cp0.o
 obj-$(CONFIG_CPU_PJ4)		+= pj4-cp0.o
 obj-$(CONFIG_IWMMXT)		+= iwmmxt.o
-obj-$(CONFIG_HW_PERF_EVENTS)	+= perf_event.o
+obj-$(CONFIG_HW_PERF_EVENTS)	+= perf_event.o perf_event_cpu.o
 AFLAGS_iwmmxt.o			:= -Wa,-mcpu=iwmmxt
 obj-$(CONFIG_ARM_CPU_TOPOLOGY)  += topology.o