msm: mdss: dp: select pin assignment D for multi-functionality

If a protocol converter or HUB or a dongle supports multi-function
to support both displayport and USB simultaneously and exposes
pin assignment D as supported one, prefer pin assignment D to be
configured on the ports.

Change-Id: Ia69987c0e15ec5f15a07ca3a0e44174ab6e5feb9
Signed-off-by: Ajay Singh Parmar <aparmar@codeaurora.org>