powerpc/perf: Use Instruction Counter value

powerpc/perf: Use Instruction Counter value

BugLink: http://bugs.launchpad.net/bugs/1667413
Since PM_INST_DISP include speculative instruction,
based on the workload the dispatch count could vary
considerably. Hence as an alternative, for completed
instruction counting, program the PM_INST_DISP event
to the MMCR* but use Instruction Counter register value.

Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
(cherry picked from linux-next commit 356d8ce3d0a4a1d7c8448c4d234121736ad3d471)
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>