msm: mdss: Correct settings when on/off happens in dest-scaler

Destination scaler can be turned off within each display commit IOCTL.
When it is disabled, the mixer dimension must be reset to match the
panel configuration. It is also required to update the destination
scaler block when there is a ON/OFF transition because all HW setting is
gone after such power event. Power event includes general suspend
resume, FB driver shutdown and reload, and auto clock gating.

CRs-Fixed: 1077684
Change-Id: I340f778583bb63d6436c4ef8f51ead77a2871625
Signed-off-by: Benjamin Chan <bkchan@codeaurora.org>