Add rockchip,rk3588-pmugrf compatible string.

Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---

Notes:
    Changes since v5:
     - new patch

 Documentation/devicetree/bindings/soc/rockchip/grf.yaml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Documentation/devicetree/bindings/soc/rockchip/grf.yaml b/Documentation/devicetree/bindings/soc/rockchip/grf.yaml
index e4fa6a07b4fa2..1309bf5ae0cdd 100644
--- a/Documentation/devicetree/bindings/soc/rockchip/grf.yaml
+++ b/Documentation/devicetree/bindings/soc/rockchip/grf.yaml
@@ -233,6 +233,7 @@ allOf:
               - rockchip,rk3399-grf
               - rockchip,rk3399-pmugrf
               - rockchip,rk3568-pmugrf
+              - rockchip,rk3588-pmugrf
               - rockchip,rv1108-grf
               - rockchip,rv1108-pmugrf
 
-- 
2.39.2