Merge tag 'u-boot-imx-20210717' of https://gitlab.denx.de/u-boot/custodians/u-boot-imx

i.MX
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- mx7ulp : fix  WDOG
- imx8 : Phytec
- USB3 support for i.MX8

CI: https://source.denx.de/u-boot/custodians/u-boot-imx/-/pipelines/8277