drm: rockchip: export functions needed by rockchip dw_hdmi bridge driver

To build the rockchip dw_hdmi driver as a module, the
rockchip_drm_encoder_get_mux_id and rockchip_drm_crtc_mode_config
functions need to be exported.
Signed-off-by: NPhilipp Zabel <p.zabel@pengutronix.de>

drivers/gpu/drm/rockchip/rockchip_drm_drv.c

@@ -390,6 +390,7 @@ int rockchip_drm_encoder_get_mux_id(struct device_node *node,
 
 	return -EINVAL;
 }
+EXPORT_SYMBOL_GPL(rockchip_drm_encoder_get_mux_id);
 
 static int compare_of(struct device *dev, void *data)
 {

drivers/gpu/drm/rockchip/rockchip_drm_vop.c

@@ -735,6 +735,7 @@ int rockchip_drm_crtc_mode_config(struct drm_crtc *crtc,
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(rockchip_drm_crtc_mode_config);
 
 static int vop_crtc_enable_vblank(struct drm_crtc *crtc)
 {