disp: msm: sde: support qsync and vrr in same atomic commit

This change adds support to program both qsync and variable
refresh rate in the same atomic commit. During vrr
usecase, if qsync is enabled, avr ctrl gets programmed
during prepare phase as well as after configuring timing
engine. This change also handles such scenarios to prevent
double programming of avr ctrl.

Change-Id: I19461423b0ae08c8204b5edeb98e3d73ce16a21b
Signed-off-by: Yashwanth <yvulapu@codeaurora.org>