msm: mdss: hdmi: reset deep_color before parsing EDID

Reset previous EDID's deep_color value before parsing new EDID.
HDMI driver is already checking if sink supports deep color or
not using hdmi_tx_sink_dc_support function. Remove dc_support
check which is redundant.

Change-Id: I7b95310ba6c7451a86ba7a536a6d59b7f0c98edd
Signed-off-by: Narender Ankam <nankam@codeaurora.org>
Signed-off-by: Ramendra Kumar <ramendra@codeaurora.org>