msm: mdss: add support for pluggable interface

Add pluggable information into panel info to let other modules
know that this interface supports HPD (Hot Plug Detect) and can
be dynamically connected or disconnected.

Change-Id: I8322b60c337cd2f46a4a500ad1a6083875f6206b
Signed-off-by: Ajay Singh Parmar <aparmar@codeaurora.org>
Signed-off-by: Sandeep Panda <spanda@codeaurora.org>