drm/i915: move has_dmc 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/b8f69cd1b6114295826c1f88be27e867c91f7df4.1660910433.git.jani.nikula@intel.com