drm/i915/dsc: Adding the new registers for DSC

Adding new DSC register which are introducted MTL onwards

Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Reviewed-by: Vandita Kulkarni <Vandita.kulkarni@intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Signed-off-by: Uma Shankar <uma.shankar@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230309062855.393087-4-suraj.kandpal@intel.com