msm: sde: add rotator busy detection and reset

During power suspend event, if rotator busy is
still set given there is no outstanding request,
rotator should be reset to avoid restarting in
invalid state after power resume event. Add
rotator busy detection logic in power suspend
event and reset accordingly.

Change-Id: Ibfd965a586dca664c2c947da6796caee30d2b527
Signed-off-by: Alan Kwong <akwong@codeaurora.org>