drm/mediatek: Add DPI sub driver

Add DPI connector/encoder to support HDMI output via the
attached HDMI bridge.

Signed-off-by: Jie Qiu <jie.qiu@mediatek.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.h b/drivers/gpu/drm/mediatek/mtk_drm_drv.h
index ac6c92b..aa93894 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_drv.h
+++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.h
@@ -53,6 +53,7 @@
 extern struct platform_driver mtk_ddp_driver;
 extern struct platform_driver mtk_disp_ovl_driver;
 extern struct platform_driver mtk_disp_rdma_driver;
+extern struct platform_driver mtk_dpi_driver;
 extern struct platform_driver mtk_dsi_driver;
 extern struct platform_driver mtk_mipi_tx_driver;