msm: kgsl: Remove A3XX soft reset

We do not need to do a soft reset of the A3XX GPUs after power on
as all the interesting registers appear to be in a reasonable power
on state. This saves 20ms during suspend/resume.

CRs-Fixed: 369927
Change-Id: Ic0dedbad367e8b402aefbf6e7746ae5b17120ac8
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>