msm: kgsl: Turn on GPU clock before setting the control flag

Make sure the GPU clocks are turned on before the control flag
is set, otherwise the clocks can never be turned on afterwards.

Change-Id: I44458e11ae09ae2499c7c2d5334e5acd43261756
Signed-off-by: Suman Tatiraju <sumant@codeaurora.org>