dt-bindings: serial: Add a new compatible string for UMS9632

The UART IP version of the ums9632 SoC project has been upgraded.
UART controller registers have added valid bits to support new features.
In order to distinguish different UART IP versions, we use sc9632-uart
to represent upgraded IP and sc9836-uart to represent old IP.

Signed-off-by: Wenhua Lin <[e-mail]>
Reviewed-by: Krzysztof Kozlowski <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

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

···
     oneOf:
       - items:
           - enum:
-              - sprd,sc9632-uart
+              - sprd,ums9632-uart
+          - const: sprd,sc9632-uart
+      - items:
+          - enum:
               - sprd,sc9860-uart
               - sprd,sc9863a-uart
               - sprd,ums512-uart
               - sprd,ums9620-uart
           - const: sprd,sc9836-uart
-      - const: sprd,sc9836-uart
+      - enum:
+          - sprd,sc9632-uart
+          - sprd,sc9836-uart
 
   reg:
     maxItems: 1