drm/msm/sde: add support in wb for new control path configuration

This change adds support in writeback to use the new interface
configuration in the control path and binds the writeback with
the input pingpong module.

Change-Id: I30a6fa5ee8b6bb8334400cfea243e07d3e7126a5
Signed-off-by: Steve Cohen <cohens@codeaurora.org>
Signed-off-by: Abhijit Kulkarni <kabhijit@codeaurora.org>