dt-bindings: usb: fix the STM32F7 DWC2 OTG HS core binding

dt-bindings: usb: fix the STM32F7 DWC2 OTG HS core binding

This patch fixes binding documentation for DWC2 controller in HS mode
found on STMicroelectronics STM32F7 SoC.
The v2 former patch [1] had been acked by Rob Herring, but v1 was merged.

[1] https://patchwork.kernel.org/patch/9925575/

Fixes: 000777dadc7e ("dt-bindings: usb: Document the STM32F7xx DWC2 ...")
Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>