drm/amd/display: Add DSC parameters logging to debugfs

[why]
Need to add new parameters to debugfs logging so
we will know what parameters DSC is using for
debug purposes. So we are adding a read function
in debugfs to read DSC status registers

Signed-off-by: Eryk Brol <eryk.brol@amd.com>
Reviewed-by: Mikita Lipski <Mikita.Lipski@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>