drm/i915/display_device: Add Check HAS_DSC for bigjoiner

Bigjoiner needs DSC, but DSC might be disabled on some platforms.
The platform check itself is not sufficient, so add a check for
DSC to reflect that.

v2: Modify the commit message to address the DSC fuse case.

Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240926134322.3728021-2-ankit.k.nautiyal@intel.com