msm: mdss: dp: fix no display issue on second connection

Video and Audio notifications from HDMI/DP driver can now be
sent separately. set/clear current display type only on receiving
video notifications.

Change-Id: I093fd0b2abd135216af67573bd7ffa4657f6af04
Signed-off-by: Narender Ankam <nankam@codeaurora.org>