drm/rockchip: remove rockchip_drm_encoder_get_mux_id

It is replaced by drm_of_encoder_active_endpoint_id.

Suggested-by: Daniel Kurtz <djkurtz@chromium.org>
Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: Yakir Yang <ykk@rock-chips.com>
[for dw_hdmi-rockchip]
Acked-by: Mark Yao <mark.yao@rock-chips.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c

@@ -204,7 +204,7 @@ static void dw_hdmi_rockchip_encoder_enable(struct drm_encoder *encoder)
 	rockchip_drm_crtc_mode_config(encoder->crtc, DRM_MODE_CONNECTOR_HDMIA,
 				      ROCKCHIP_OUT_MODE_AAAA);
 
-	mux = rockchip_drm_encoder_get_mux_id(hdmi->dev->of_node, encoder);
+	mux = drm_of_encoder_active_endpoint_id(hdmi->dev->of_node, encoder);
 	if (mux)
 		val = HDMI_SEL_VOP_LIT | (HDMI_SEL_VOP_LIT << 16);
 	else