drm/msm: update intf timing and flush cfg for dsc-over-dp

Update DP interface timing engine configurations as per
hw programming requirements for dsc-over-dp usecases.

Change-Id: Ibb18b71340cbd71e87c5caef11c9c29804911ac2
Signed-off-by: Govinda Rajulu Chenna <gchenna@codeaurora.org>