msm: mdss: Correct video interface setup for AVR feature

When DFPS is not being used and AVR is enabled, it is necessary to
program the video interface with correct setting, including a timing
engine flush and DSI video control.

CRs-Fixed: 1109202
Change-Id: Iadb24da27715353ac3d4825ad053a1c039bd2ee6
Signed-off-by: Benjamin Chan <bkchan@codeaurora.org>