drm/radeon: Fix WARN_ON if DRM_DP_AUX_CHARDEV is enabled

Rafael Antognolli's new DRM_DP_AUX_CHARDEV feature causes a WARN_ON
if drm_dp_aux->dev == drm_connector->kdev and drm_dp_aux_unregister()
is called after drm_connector_unregister(). radeon is the only driver
affected by this besides i915. (amdgpu calls drm_dp_aux_unregister()
before drm_connector_unregister().)

Cc: Rafael Antognolli <rafael.antognolli@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: NLukas Wunner <lukas@wunner.de>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/radeon_display.c

@@ -1686,6 +1686,9 @@ void radeon_modeset_fini(struct radeon_device *rdev)
 	radeon_fbdev_fini(rdev);
 	kfree(rdev->mode_info.bios_hardcoded_edid);
 
+	/* free i2c buses */
+	radeon_i2c_fini(rdev);
+
 	if (rdev->mode_info.mode_config_initialized) {
 		radeon_afmt_fini(rdev);
 		drm_kms_helper_poll_fini(rdev->ddev);
@@ -1693,8 +1696,6 @@ void radeon_modeset_fini(struct radeon_device *rdev)
 		drm_mode_config_cleanup(rdev->ddev);
 		rdev->mode_info.mode_config_initialized = false;
 	}
-	/* free i2c buses */
-	radeon_i2c_fini(rdev);
 }
 
 static bool is_hdtv_mode(const struct drm_display_mode *mode)