dt-bindings: serial: 8250: Add nuvoton,wpcm450-uart

Add a compatible string for the UART inside the Nuvoton WPCM450 SoC.
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Link: https://lore.kernel.org/r/20210320181610.680870-5-j.neuschaefer@gmx.netSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/serial/8250.yaml

@@ -55,6 +55,7 @@ properties:
       - const: aspeed,ast2500-vuart
       - const: intel,xscale-uart
       - const: mrvl,pxa-uart
+      - const: nuvoton,wpcm450-uart
       - const: nuvoton,npcm750-uart
       - const: nvidia,tegra20-uart
       - const: nxp,lpc3220-uart