dt-bindings: arm: Add Gateworks i.MX8M Plus gw73xx-2x board

Add DT compatible string for a Gateworks GW73xx-2x board based on
the i.MX8M Plus SoC from NXP.

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

Author: Gateworks

Documentation/devicetree/bindings/arm/fsl.yaml

@@ -1034,6 +1034,7 @@ properties:
               - fsl,imx8mp-evk            # i.MX8MP EVK Board
               - gateworks,imx8mp-gw71xx-2x # i.MX8MP Gateworks Board
               - gateworks,imx8mp-gw72xx-2x # i.MX8MP Gateworks Board
+              - gateworks,imx8mp-gw73xx-2x # i.MX8MP Gateworks Board
               - gateworks,imx8mp-gw74xx   # i.MX8MP Gateworks Board
               - gateworks,imx8mp-gw7905-2x # i.MX8MP Gateworks Board
               - polyhex,imx8mp-debix      # Polyhex Debix boards