msm: kgsl: Decrease requirements to access SPTP regs

Instead of checking that the GMU was probed and enabled,
only check that the GMU was probed when turning SPTPRAC
on and off. We only need the mapping to use registers.
This is needed for usecases where the GMU is disabled.
In these cases, these registers still need to be accessed.

CRs-Fixed: 2017390
Change-Id: Id2d08cb84aa16c4f8bb012f5b19e4c5551a13072
Signed-off-by: Kyle Piefer <kpiefer@codeaurora.org>