dt-bindings: usb: usb-nop-xceiv: Repurpose vbus-regulator

The vbus-regulator property was never actually read from the device tree.
Introduce a new property vbus-supply to represent the regulator powering
the VBUS when acting as an A-Device. This supply will be enabled and
disabled as necessary. Note that this is different from vbus-regulator,
which represented the available current available to draw from VBUS in
B-Device mode. Because no one was using vbus-regulator, remove it.

Signed-off-by: Sean Anderson <[e-mail]>
Reviewed-by: Linus Walleij <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

Documentation/devicetree/bindings/usb/usb-nop-xceiv.yaml

···
     description: Should specify the GPIO detecting a VBus insertion
     maxItems: 1
 
-  vbus-regulator:
-    description: Should specify the regulator supplying current drawn from
-      the VBus line.
-    $ref: /schemas/types.yaml#/definitions/phandle
+  vbus-supply:
+    description: regulator supplying VBUS. It will be enabled and disabled
+                 dynamically in OTG mode. If the regulator is controlled by a
+                 GPIO line, this should be modeled as a regulator-fixed and
+                 referenced by this supply.
 
   wakeup-source:
     description:
···
         vcc-supply = <&hsusb1_vcc_regulator>;
         reset-gpios = <&gpio1 7 GPIO_ACTIVE_LOW>;
         vbus-detect-gpio = <&gpio2 13 GPIO_ACTIVE_HIGH>;
-        vbus-regulator = <&vbus_regulator>;
+        vbus-supply = <&vbus_regulator>;
         #phy-cells = <0>;
     };