msm: mdss: fix Display Port boot-up with default resolution

The Display Port driver treats 480p as the default resolution
during driver probe for panel info initialization. At this point
of time, the EDID data of the sink will not be available and the bpp
of sink is set as 18 by default. If a sink is connected first time on
boot-up with 480p resolution, the panel information doesn't get
updated since current VIC and new VIC are the same. If the panel bpp
specified in EDID is not 18, display might fail to come up. Handle
this issue by updating the panel info every time when a DP connection
is established independent of whether VIC changed or not.

Change-Id: Icb8809986724ac3bad6df3721c9efd4815b32853
Signed-off-by: Padmanabhan Komanduru <pkomandu@codeaurora.org>