dt-bindings: mfd: sprd: Add support for UMS9620

Add bindings for Unisoc UMS9620 system global registers which provide
register maps for clocks.
Signed-off-by: Chunyan Zhang <chunyan.zhang@unisoc.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20231215085630.984892-2-chunyan.zhang@unisoc.comSigned-off-by: Lee Jones <lee@kernel.org>

Documentation/devicetree/bindings/mfd/sprd,ums512-glbreg.yaml

@@ -19,7 +19,9 @@ description:
 properties:
   compatible:
     items:
-      - const: sprd,ums512-glbregs
+      - enum:
+          - sprd,ums512-glbregs
+          - sprd,ums9620-glbregs
       - const: syscon
       - const: simple-mfd