dt-bindings: usb: renesas,usb-xhci: Document RZ/V2M support

Document the RZ/V2M SoC bindings.
The RZ/V2M SoC is a little different to the R-Car implementations.
You can access the registers associated with the currently set DRD mode,
therefore as part of init, we have to set the DRD mode to host.

Signed-off-by: Biju Das <[e-mail]>
Reviewed-by: Rob Herring <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

Documentation/devicetree/bindings/usb/renesas,usb-xhci.yaml

···
   - Lad Prabhakar <[e-mail]>
   - Yoshihiro Shimoda <[e-mail]>
 
-allOf:
-  - $ref: "usb-xhci.yaml"
-
 properties:
   compatible:
     oneOf:
···
               - renesas,xhci-r8a77965 # R-Car M3-N
               - renesas,xhci-r8a77990 # R-Car E3
           - const: renesas,rcar-gen3-xhci # R-Car Gen3 and RZ/G2
+      - items:
+          - enum:
+              - renesas,r9a09g011-xhci # RZ/V2M
+              - renesas,r9a09g055-xhci # RZ/V2MA
+          - const: renesas,rzv2m-xhci  # RZ/{V2M, V2MA}
 
   reg:
     maxItems: 1
···
     maxItems: 1
 
   clocks:
-    maxItems: 1
+    minItems: 1
+    items:
+      - description: Main clock for host
+      - description: Register access clock
+
+  clock-names:
+    minItems: 1
+    items:
+      - const: axi
+      - const: reg
 
   phys:
     maxItems: 1
···
   - clocks
   - power-domains
   - resets
+
+allOf:
+  - $ref: usb-xhci.yaml
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - renesas,rzv2m-xhci
+    then:
+      properties:
+        clocks:
+          minItems: 2
+        clock-names:
+          minItems: 2
+      required:
+        - clock-names
+    else:
+      properties:
+        clocks:
+          maxItems: 1
 
 unevaluatedProperties: false