drm/msm/sde: Add support for DSC 4 4 2 Topology

Add support for DSC 4 4 2 topology. With this, All 4 encoders
can be used so that maximum 8 slices per line can be encoded.

Change-Id: I34381986c4016af7e2975d34320e4ba4e86c7a73
Signed-off-by: Vishnuvardhan Prodduturi <vproddut@codeaurora.org>