drm/i915: move has_dsc to runtime info

If it's modified runtime, it's runtime info.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Maarten Lankhort <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/0e2646e5fdaad2785678b4f140091b3d91b97f7e.1660910433.git.jani.nikula@intel.com