drm/bridge/synopsys: Add MIPI DSI host controller bridge

Add a Synopsys Designware MIPI DSI host DRM bridge driver, based on the
Rockchip version from rockchip/dw-mipi-dsi.c with phy & bridge APIs.

Signed-off-by: Philippe CORNU <philippe.cornu@st.com>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Link: https://patchwork.freedesktop.org/patch/msgid/1500277223-29553-5-git-send-email-philippe.cornu@st.com

drivers/gpu/drm/bridge/synopsys/Kconfig

@@ -22,3 +22,9 @@ config DRM_DW_HDMI_I2S_AUDIO
 	help
 	  Support the I2S Audio interface which is part of the Synopsys
 	  Designware HDMI block.
+
+config DRM_DW_MIPI_DSI
+	tristate
+	select DRM_KMS_HELPER
+	select DRM_MIPI_DSI
+	select DRM_PANEL_BRIDGE