dt-bindings: serial: fsl-lpuart: Add i.MX8DXL compatible

Add i.MX8DXL lpuart compatible to the bindings documentation.
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Abel Vesa <abel.vesa@nxp.com>
Link: https://lore.kernel.org/r/20220118131715.2051965-1-abel.vesa@nxp.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/serial/fsl-lpuart.yaml

@@ -28,7 +28,9 @@ properties:
               - fsl,imx8ulp-lpuart
           - const: fsl,imx7ulp-lpuart
       - items:
-          - const: fsl,imx8qm-lpuart
+          - enum:
+              - fsl,imx8qm-lpuart
+              - fsl,imx8dxl-lpuart
           - const: fsl,imx8qxp-lpuart
 
   reg: