perf/POWER7: Make some POWER7 events available in sysfs

Make some POWER7-specific perf events available in sysfs.

	$ /bin/ls -1 /sys/bus/event_source/devices/cpu/events/
	branch-instructions
	branch-misses
	cache-misses
	cache-references
	cpu-cycles
	instructions
	PM_BRU_FIN
	PM_BRU_MPRED
	PM_CMPLU_STALL
	PM_CYC
	PM_GCT_NOSLOT_CYC
	PM_INST_CMPL
	PM_LD_MISS_L1
	PM_LD_REF_L1
	stalled-cycles-backend
	stalled-cycles-frontend

where the 'PM_*' events are POWER specific and the others are the
generic events.

This will enable users to specify these events with their symbolic
names rather than with their raw code.

	perf stat -e 'cpu/PM_CYC' ...

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/20130123062528.GE13720@us.ibm.com


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>