uboot-phytec

Merge tag 'video-for-v2020.01-rc2' of https://gitlab.denx.de/u-boot/custodians/u-boot-video

- fix i.MX6ULL evk black screen observed while reboot stress tests
- remove "synopsys,dw-mipi-dsi" compatible to reduce the device tree
  differences between Linux and U-Boot for stm32mp1 platform