Revert "msm: kgsl: Remove sscanf() from kgsl_pwrctrl.c"

This reverts commit a5ded29a73fa504e10d0836e308303ed6baad233.
msm: kgsl: Allow GPU start to run in a high priority queue

The GPU start sequence needs to run with low latency when coming
out of slumber for the first draw command. For those cases allow the
start function to be queued into a high priority workqueue to reduce
the chance of it getting scheduled out.

Change-Id: Ic0dedbada7ef4d63b54e826862fbefdfb71a092a
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>

Conflicts:
	drivers/gpu/msm/adreno.c
	drivers/gpu/msm/adreno.h
	drivers/gpu/msm/kgsl.c