drm/msm/sde: use internal set property for custom property reset

DRM framework no longer exports it's set property functions for planes
and connectors to sub-drivers.  For custom properties these calls would
normally come back to the SDE layer anyway, so just call the SDE
functions directly.  DRM set property helper functions and legacy
(non-atomic) set property functions have also been deprecated or are
no longer called on atomic sub-drivers so these have been removed
from SDE as well.

Change-Id: Ie083e49781e7e841e08045cc8aa61ad27633e7f5
Signed-off-by: Steve Cohen <cohens@codeaurora.org>