disp: msm: sde: fix vsync wakeup time

Current wakeup time is surpassing next vsync and not being used.
This change will use mdp transfer time calculated by dsi to compute
line time in command mode. In video mode, fps will be used to compute
the line time. This line time will be used with current interface
line count to calculate time until the next vsync.

Change-Id: I0b6fc396711ade95ecf95755a907280309af223e
Signed-off-by: Samantha Tran <samtran@codeaurora.org>