msm: kgsl: Make sure regulators are ON before GPU clocks are forced on

The debug option to always ON the GPU clocks does not check the regulator
state. If the user tries to set this option while GPU is in Slumber state
then enabling clocks will fail.

Make sure we enable the GPU regulators before enabling its clocks.

Change-Id: Id77773224c674fe2e1b6179a039750b24e5e5f87
Signed-off-by: Rajesh Kemisetti <rajeshk@codeaurora.org>