drm/i915: Handle MST in intel_dp_has_dsc()

Utilize intel_dp_has_dsc() for MST as well.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240517145356.26103-4-ville.syrjala@linux.intel.com


Reviewed-by: Jani Nikula <jani.nikula@intel.com>