drm/msm: drop drm_gem_object_put_locked()

No idea why we were still using this.  It certainly hasn't been needed
for some time.  So drop the pointless twin codepaths.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Acked-by: Christian König <christian.koenig@amd.com>
Link: https://lore.kernel.org/r/20210728010632.2633470-4-robdclark@gmail.com


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