x86, perfcounters: rename intel_arch_perfmon.h => perf_counter.h

Impact: rename include file

We'll be providing an asm/perf_counter.h to the generic perfcounter code,
so use the already existing x86 file for this purpose and rename it.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/apic.c b/arch/x86/kernel/apic.c
index 0579ec1..4f859ac 100644
--- a/arch/x86/kernel/apic.c
+++ b/arch/x86/kernel/apic.c
@@ -31,7 +31,7 @@
 #include <linux/dmi.h>
 #include <linux/dmar.h>
 
-#include <asm/intel_arch_perfmon.h>
+#include <asm/perf_counter.h>
 #include <asm/atomic.h>
 #include <asm/smp.h>
 #include <asm/mtrr.h>