drm/msm/dpu: remove resource pool manager

resource pool manager utility was introduced to manage
rotator sessions. Removing the support as the rotator
feature doesn't exist.

changes in v4:
	- none
changes in v5:
	- none

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