dt-bindings: usb: Bring back phy-names

While the original bindings that were superseeded by the YAML schemas
didn't mention that phy-names was needed, it turns out that phy-names is
required if phys is set according to phy/phy-bindings.txt.

Let's add back those properties.

Fixes: 14ec072a19ad ("dt-bindings: usb: Convert USB HCD generic binding to YAML")
Fixes: c93bcace1098 ("dt-bindings: usb: Convert the generic OHCI binding to YAML")
Fixes: c3e2485d5f4f ("dt-bindings: usb: Convert the generic EHCI binding to YAML")
Reported-by: Emmanuel Vadot <[e-mail]>
Signed-off-by: Maxime Ripard <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

Documentation/devicetree/bindings/usb/generic-ehci.yaml

···
     description:
       Set this flag to force EHCI reset after resume.
 
-  phys: true
+  phys:
+    description: PHY specifier for the USB PHY
+
+  phy-names:
+    const: usb
 
 required:
   - compatible
···
         interrupts = <39>;
         clocks = <&ahb_gates 1>;
         phys = <&usbphy 1>;
+        phy-names = "usb";
     };
 
 ...

Documentation/devicetree/bindings/usb/generic-ohci.yaml

···
     description:
       Overrides the detected port count
 
-  phys: true
+  phys:
+    description: PHY specifier for the USB PHY
+
+  phy-names:
+    const: usb
 
 required:
   - compatible
···
           interrupts = <64>;
           clocks = <&usb_clk 6>, <&ahb_gates 2>;
           phys = <&usbphy 1>;
+          phy-names = "usb";
       };
 
 ...

Documentation/devicetree/bindings/usb/usb-hcd.yaml

···
     description:
       List of all the USB PHYs on this HCD
 
+  phy-names:
+    description:
+      Name specifier for the USB PHY
+
 examples:
   - |
     usb {
         phys = <&usb2_phy1>, <&usb3_phy1>;
+        phy-names = "usb";
     };