msm: kgsl: Dump ringbuffer in snapshot when GX GDSC is off

Allow ringbuffer dump in snapshot when GX is off, as it is
not having any dependency with the GX GDSC sate.

Change-Id: I73f55ae983647189617264973446413a9cc38b04
Signed-off-by: Hareesh Gundu <hareeshg@codeaurora.org>