drm/msm/a6xx: Fix uinitialized use of gpu_scid

Avoid a possible uninitialized use of gpu_scid variable to fix the
below smatch warning:
	drivers/gpu/drm/msm/adreno/a6xx_gpu.c:1480 a6xx_llc_activate()
	error: uninitialized symbol 'gpu_scid'.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Akhil P Oommen <akhilpo@codeaurora.org>
Link: https://lore.kernel.org/r/20211118154903.3.Ie4ac321feb10168af569d9c2b4cf6828bed8122c@changeid


Signed-off-by: Rob Clark <robdclark@chromium.org>