dt-bindings: mtk-uart: add mt6765 uart bindings

Add documentation for mt6765 uart dt-bindings
Signed-off-by: Mars Cheng <mars.cheng@mediatek.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/serial/mtk-uart.txt

@@ -8,6 +8,7 @@ Required properties:
   * "mediatek,mt6582-uart" for MT6582 compatible UARTS
   * "mediatek,mt6589-uart" for MT6589 compatible UARTS
   * "mediatek,mt6755-uart" for MT6755 compatible UARTS
+  * "mediatek,mt6765-uart" for MT6765 compatible UARTS
   * "mediatek,mt6795-uart" for MT6795 compatible UARTS
   * "mediatek,mt6797-uart" for MT6797 compatible UARTS
   * "mediatek,mt7622-uart" for MT7622 compatible UARTS