dt-bindings: serial: fsl-linflexuart: add compatible for S32G2

Add a compatible string for the uart binding of NXP S32G2 platforms. Here
we use "s32v234-linflexuart" as fallback since the current linflexuart
driver can still work on S32G2.
Signed-off-by: Chester Lin <clin@suse.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

Documentation/devicetree/bindings/serial/fsl,s32-linflexuart.yaml

@@ -20,9 +20,11 @@ allOf:
 
 properties:
   compatible:
-    description: The LINFlexD controller in UART mode.
-    items:
+    oneOf:
       - const: fsl,s32v234-linflexuart
+      - items:
+          - const: nxp,s32g2-linflexuart
+          - const: fsl,s32v234-linflexuart
 
   reg:
     maxItems: 1