uboot-phytec

Merge tag 'u-boot-stm32-20190628' of https://gitlab.denx.de/u-boot/custodians/u-boot-stm

STM32 MCU fixes/cleanup:
- Fix SPL console for STM32F769 Discovery
- Fix Memory Protection Unit size for STM32F4 series
- Cleanup DT for STM32F746 Discovery