drm/msm/dpu: remove LOCK/CLEAR support in RM

DPU had the support to LOCK the hw resources in
atomic check and CLEAR the locked resources explicitly
through custom property values. Now that DPU is
stripped off of all the custom properties, the RM
handlers for this feature will be no-op's. This change
gets rid of all its references.

changes in v5:
	- Introduced in the series.

Signed-off-by: Jeykumar Sankaran <jsanka@codeaurora.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>