Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32f7/STM32F730/OTG_FS_PWRCLK/OTG_FS_PCGCCTL#0x0
OTG_FS power and clock gating control register (OTG_FS_PCGCCTL)
Stop PHY clock
Gate HCLK
PHY Suspended
https://github.com/modm-io/cmsis-svd-stm32