msm: kgsl: Pass multiple register sets to the snapshot register dump

Expand the snapshot register dump helper function to support multiple
sets of registers.  This will be useful for derivative GPUS that
use a global subset of registers and add a few new ones.  This will
not be useful for chipsets that have extensive changes to existing
registers.

Change-Id: Ic0dedbad05bcc3b5a3a0cc933659959965ff5817
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>