dt-bindings: serial: Add compatible for Mediatek MT8183

This adds dt-binding documentation of uart for Mediatek MT8183 SoC
Platform.

Signed-off-by: Erin Lo <erin.lo@mediatek.com>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

@@ -16,6 +16,7 @@ Required properties:
   * "mediatek,mt8127-uart" for MT8127 compatible UARTS
   * "mediatek,mt8135-uart" for MT8135 compatible UARTS
   * "mediatek,mt8173-uart" for MT8173 compatible UARTS
+  * "mediatek,mt8183-uart", "mediatek,mt6577-uart" for MT8183 compatible UARTS
   * "mediatek,mt6577-uart" for MT6577 and all of the above
 
 - reg: The base address of the UART register bank.