Merge tag 'u-boot-imx-20201227' of https://gitlab.denx.de/u-boot/custodians/u-boot-imx

Fixes for 2021.1
----------------

CI: https://gitlab.denx.de/u-boot/custodians/u-boot-imx/-/pipelines/5680

- fixes for Variscite dart6ul
- imx8mp : increase malloc area
- fixes for bx50v3
- imx8m: HS400ES and UHS for EVK
- imx8qm-rom7720: fix phy bind