powerpc/perf: Remove PME_ prefix for power7 events

BugLink: http://bugs.launchpad.net/bugs/1578211



We used the PME_ prefix earlier to avoid some macro/variable name
collisions.  We have since changed the way we define/use the event
macros so we no longer need the prefix.

By dropping the prefix, we keep the the event macros consistent with
their official names.

Reported-by: Michael Ellerman <ellerman@au1.ibm.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
(cherry picked from commit d4969e24)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Acked-by: Brad Figg <brad.figg@canonical.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>