synopsys dcd_dwc2 VBUS handling

[ClarkyKent]

Currently I am using STM32h743x MCU which is powered by battery and i am using TinyUSB with FreeRTOS OS for CDC. If there is no USB when board is powered up, it tries to connect by calling dcd_connect() . By doing this MCU enters in reset and loops between USB connect and reset.

Proposed solution It should be handled like it is done in one of the PR #1094 . At least if VBUS sensing is enabled.

We should be able to get an interrupt on SRQINT in OTG_GINTSTS.