drm/msm/sde: remove unused functions in sde crtc

Clean up the sde crtc by unregistering function stubs from
unsupported or unused API callbacks.

Change-Id: I52de3b3ea501a6995235a3d8b6e4eb841e4b1f7b
Signed-off-by: Lloyd Atkinson <latkinso@codeaurora.org>
1 file changed