drm: bridge: dw-hdmi: Add Documentation on supported input formats

This patch adds a new DRM documentation entry and links to the input
format table added in the dw_hdmi header.
Reviewed-by: Archit Taneja <architt@codeaurora.org>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>

Documentation/gpu/bridge/dw-hdmi.rst

+=======================================================
+ drm/bridge/dw-hdmi Synopsys DesignWare HDMI Controller
+=======================================================
+
+Synopsys DesignWare HDMI Controller
+===================================
+
+This section covers everything related to the Synopsys DesignWare HDMI
+Controller implemented as a DRM bridge.
+
+Supported Input Formats and Encodings
+-------------------------------------
+
+.. kernel-doc:: include/drm/bridge/dw_hdmi.h
+   :doc: Supported input formats and encodings

Documentation/gpu/index.rst

@@ -15,6 +15,7 @@ Linux GPU Driver Developer's Guide
    vc4
    vga-switcheroo
    vgaarbiter
+   bridge/dw-hdmi
    todo
 
 .. only::  subproject and html