drm/msm/sde: support command mode autorefresh

Add support for the autorefresh feature in which hardware
automatically kicks off the previously sent frame to the
command mode panel, similar to a video mode panel.

Change-Id: I1fa339784330c19241433a44acab5dabf9910ce8
Signed-off-by: Lloyd Atkinson <latkinso@codeaurora.org>