msm: kgsl: Move a6xx perfcounters to target specific

Migrate the a6xx perfcounters to target specific.  These counters
constitute the bulk of the specialized enable operations.  This also is
the place where VBIF gets replaced with GBIF so a630 gets its own set of
perfcounters and we have to double up the functions for a6xx.

Change-Id: Ic0dedbadf04fcafb46816c8b970af3bd32a57c7b
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>