drm/msm/sde: add DSC encoder support for display topologies

Add display stream compression support for sde drm driver. Read
DSC compression details of the panel from the display driver and
configure SDE as per the topology selected for the display panel.
Patch adds support for 3 different DSC compression modes:
(1) Single DSC encoder mode
(2) Dual DSC encoder merge mode
(3) Dual DSC encoder mode

Change-Id: Ibbb8fe37d0e01cc84c740d55e1d9c5c58da9d2d7
Signed-off-by: Alexander Beykun <abeykun@codeaurora.org>
Signed-off-by: Jeykumar Sankaran <jsanka@codeaurora.org>