dt-bindings: phy: renesas,usb2-phy: Document RZ/V2L phy bindings

Document USB phy bindings for RZ/V2L SoC. RZ/V2L USB phy is identical to
one found on the RZ/G2L SoC. No driver changes are required as generic
compatible string "renesas,rzg2l-usb2-phy" will be used as a fallback.

While at it, drop the comment "RZ/G2L family" for "renesas,rzg2l-usb2-phy"
compatible string as this will avoid changing the line for every new SoC
addition.

Signed-off-by: Lad Prabhakar <[e-mail]>
Reviewed-by: Biju Das <[e-mail]>
Acked-by: Yoshihiro Shimoda <[e-mail]>
Reviewed-by: Geert Uytterhoeven <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Vinod Koul <[e-mail]>

Documentation/devicetree/bindings/phy/renesas,usb2-phy.yaml

···
       - items:
           - enum:
               - renesas,usb2-phy-r9a07g044 # RZ/G2{L,LC}
-          - const: renesas,rzg2l-usb2-phy  # RZ/G2L family
+              - renesas,usb2-phy-r9a07g054 # RZ/V2L
+          - const: renesas,rzg2l-usb2-phy
 
   reg:
     maxItems: 1