drm/msm/dp: update link parameters before PSM call

Move panel initialization into host initialization so that
the panel is initialized along with other sub-modules. Call
link probe in panel initialization to initialize the link
parameters before any of the functionality, like PSM which
need these parameters, doesn't fail to execute and send
DP_SET_POWERSTATE(600h) during DP Hot Plug.

Change-Id: I0c5a61679d5b1d842435ec290e710673db5f8109
Signed-off-by: Ajay Singh Parmar <aparmar@codeaurora.org>