USBX documentation improvement

[TakahiroMuranaka227]

Improvement Item

The explanation for Host Video Class API is not described in the following USBX document. https://learn.microsoft.com/en-us/azure/rtos/usbx/

Request

Please add the explanation for Host Video Class API in the following USBX document. https://learn.microsoft.com/en-us/azure/rtos/usbx/

[xiaocq2001]

Thanks for the feedback. We will update that later.