dt-bindings: display: sun4i-drm: Add R40 TV TCON description

TCON description is expanded with R40 TV TCON compatible. It is a bit
special, because it is connected to TCON TOP instead directly to mixer
and it needs special handling.
Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180710203511.18454-7-jernej.skrabec@siol.net

Documentation/devicetree/bindings/display/sunxi/sun4i-drm.txt

@@ -147,6 +147,7 @@ Required properties:
    * allwinner,sun8i-a33-tcon
    * allwinner,sun8i-a83t-tcon-lcd
    * allwinner,sun8i-a83t-tcon-tv
+   * allwinner,sun8i-r40-tcon-tv
    * allwinner,sun8i-v3s-tcon
    * allwinner,sun9i-a80-tcon-lcd
    * allwinner,sun9i-a80-tcon-tv
@@ -181,7 +182,7 @@ For TCONs with channel 0, there is one more clock required:
 For TCONs with channel 1, there is one more clock required:
    - 'tcon-ch1': The clock driving the TCON channel 1
 
-When TCON support LVDS (all TCONs except TV TCON on A83T and those found
+When TCON support LVDS (all TCONs except TV TCONs on A83T, R40 and those found
 in A13, H3, H5 and V3s SoCs), you need one more reset line:
    - 'lvds': The reset line driving the LVDS logic