Various fixes for errors ound while debugging OTG on L496

STM32, STM32 L4, and STM32 M4: USB OTGFS DMA trace output fix
STM32: Add dump buffer feature to stm32 F4 series
STM32 and STM32 L4: Fix bad USB OTGFS register address
STM32 L4:  Fix typo in USB OTGFS register usage
STM32 L4:  Add check in USB OTGFS driver to assure that SYSCFG is enabled
Nucleo-L496ZG:  Make HSE on Nucleo-L496ZG default to enable USB