dt-bindings: soc: rockchip: Document RV1126 pmugrf

Document compatible string for Rockchip RV1126 pmugrf.
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jagan Teki <jagan@edgeble.ai>
Link: https://lore.kernel.org/r/20220907160207.3845791-8-jagan@edgeble.aiSigned-off-by: Heiko Stuebner <heiko@sntech.de>

Documentation/devicetree/bindings/soc/rockchip/grf.yaml

@@ -49,6 +49,7 @@ properties:
               - rockchip,rv1108-grf
               - rockchip,rv1108-pmugrf
               - rockchip,rv1126-grf
+              - rockchip,rv1126-pmugrf
           - const: syscon
           - const: simple-mfd