drm/i915: Skip intel_modeset_pipe_config_late() if the pipe is not enabled

No sense in calling intel_modeset_pipe_config_late() for a disabled
pipe.

Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220907091057.11572-14-ville.syrjala@linux.intel.com