Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Keil/AT32F405xx_v2/USB_OTGHS_GLOBAL/GRXFSIZ#0x0
OTGHS Receive FIFO size register (OTGHS_GRXFSIZ)
RxFIFO depth
https://github.com/cmsis-svd/cmsis-svd-data