msm: kgsl: Read speed bin information for 8996v3

There are multiple speed bin levels for the 8996v3 target.  Read
the fused speed bin value and choose the appropriate set of
powerlevels.

Change-Id: Ic0dedbad51ec9716bdd623647cad4d699855a62c
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>