Make the generic perf events in POWER7 available via sysfs.

	$ ls /sys/bus/event_source/devices/cpu/events
	branch-instructions
	branch-misses
	cache-misses
	cache-references
	cpu-cycles
	instructions
	stalled-cycles-backend
	stalled-cycles-frontend

	$ cat /sys/bus/event_source/devices/cpu/events/cache-misses
	event=0x400f0

This patch is based on commits that implement this functionality on x86.
Eg:
	commit a4747393
	Author: Jiri Olsa <jolsa@redhat.com>
	Date:   Wed Oct 10 14:53:11 2012 +0200

	    perf/x86: Make hardware event translations available in sysfs

Changelog:[v2]
	[Jiri Osla] Drop EVENT_ID() macro since it is only used once.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Anton Blanchard <anton@au1.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: linuxppc-dev@ozlabs.org
Link: http://lkml.kernel.org/r/20130123062454.GD13720@us.ibm.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>