This change enforces dp, dsi and the sde drivers to use the
drm framework defined dsc_config data structure. As a part of this,
it introduces the sde_dsc_helper API to configure the dsc params
and creating a PPS command. Earlier each driver implemented it's
private versions leading to duplication of code. Additionaly the
helper api supports DSC spec 1.2 422 and 420 mode.
Change-Id: I25933fab08cdabbc6787079926885d1a78945e97
Signed-off-by: Abhijit Kulkarni <kabhijit@codeaurora.org>
