clk: msm: gdsc: Support new enable sequence for GDSC_GPU_GX

On some targets, in order to flush out the demet cells in the
GFX PMIC domain, the GFX SW reset should be asserted and then
de-asserted before enabling the gdsc_gpu_gx. Add support in
the GDSC framework for the same.

Change-Id: I62e9d6324304f9fe56f446bf51d514ae139c8482
Signed-off-by: Deepak Katragadda <dkatraga@codeaurora.org>