drm: Make the .mode_fixup() operations mode argument a const pointer

The passed mode must not be modified by the operation, make it const.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/radeon/atombios_dp.c

@@ -608,7 +608,7 @@ int radeon_dp_get_panel_mode(struct drm_encoder *encoder,
 }
 
 void radeon_dp_set_link_config(struct drm_connector *connector,
-			       struct drm_display_mode *mode)
+			       const struct drm_display_mode *mode)
 {
 	struct radeon_connector *radeon_connector = to_radeon_connector(connector);
 	struct radeon_connector_atom_dig *dig_connector;