msm: mdss: add support to send dcs cmds by left port only in video mode

In the current implementation, the existing feature flag to send DCS
commands only by the left controller is parsed only for command mode
panels. Extend this support to include video mode panels as well.

Change-Id: I32c5d96b514a8c4cb90fd320d589fe4252e92133
Signed-off-by: Naseer Ahmed <naseer@codeaurora.org>