dt-bindings: usb: dwc2: add compatible "intel,socfpga-agilex-hsotg"

Add the compatible "intel,socfpga-agilex-hsotg" to the DWC2
implementation, because the Agilex DWC2 implementation does not support
clock gating.

Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>