dt-bindings: usb: generic-ehci: document spurious-oc flag

Over-current reporting isn't supported on some platforms such as bcm63xx.
These devices will incorrectly report over-current if this flag isn't properly
activated.

Acked-by: Rob Herring <[e-mail]>
Signed-off-by: Álvaro Fernández Rojas <[e-mail]>
Acked-by: Alan Stern <[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.
 
+  spurious-oc:
+    $ref: /schemas/types.yaml#/definitions/flag
+    description:
+      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: