dt-bindings: usb: ti,j721e-usb: drop assigned-clocks

The meta schema from DT schema already defines assigned-clocks, so there
is no need for device schema to mention it at all. There are also no
benefits of having it here.

Signed-off-by: Krzysztof Kozlowski <[e-mail]>
Acked-by: Rob Herring <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

Documentation/devicetree/bindings/usb/ti,j721e-usb.yaml

···
       VBUS pin of the SoC via a 1/3 voltage divider.
     type: boolean
 
-  assigned-clocks:
-    maxItems: 1
-
-  assigned-clock-parents:
-    maxItems: 1
-
   '#address-cells':
     const: 2