dt-bindings: serial: Add a new compatible string for SC9863A

SC9863A use the same serial device which SC9836 uses.
Signed-off-by: Chunyan Zhang <chunyan.zhang@unisoc.com>
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/serial/sprd-uart.yaml

@@ -18,6 +18,7 @@ properties:
       - items:
           - enum:
               - sprd,sc9860-uart
+              - sprd,sc9863a-uart
           - const: sprd,sc9836-uart
       - const: sprd,sc9836-uart