dt-bindings: usb: generic-ehci: allow usb-hcd schema properties

Allow properties and usb-device child nodes as defined in usb-hcd.yaml, by
using unevaluatedProperties: false. By the way, remove the "companion"
property as it's redundant with usb-hcd.yaml.
As example, this allows an onboard hub, to be described in generic-ehci
controller node:
usb {
  compatible = "generic-ehci";
  #address-cells = <1>;
  #size-cells = <0>;
  /* onboard HUB */
  hub@1 {
    compatible = "usb424,2514";
    reg = <1>;
    vdd-supply = <&v3v3>;
  };
};

Without this, dtbs_check complains on '#address-cells', '#size-cells',
'hub@1' do not match any of the regexes: 'pinctrl-[0-9]+'
From schema: ..../generic-ehci.yaml

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Link: https://lore.kernel.org/r/20220726080708.162547-2-fabrice.gasnier@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

@@ -130,11 +130,6 @@ properties:
       Set this flag to indicate that the hardware sometimes turns on
       the OC bit when an over-current isn't actually present.
 
-  companion:
-    $ref: /schemas/types.yaml#/definitions/phandle
-    description:
-      Phandle of a companion.
-
   phys:
     minItems: 1
     maxItems: 3
@@ -155,7 +150,7 @@ required:
   - reg
   - interrupts
 
-additionalProperties: false
+unevaluatedProperties: false
 
 examples:
   - |