Merge tag 'u-boot-imx-next-20240317' of...

Merge tag 'u-boot-imx-next-20240317' of https://gitlab.denx.de/u-boot/custodians/u-boot-imx into next

CI: https://source.denx.de/u-boot/custodians/u-boot-imx/-/pipelines/19975

- Select polling-rate from cpu-thermal devicetree node on imx_tmu.
- Re-organize the U-Boot environment and add RAUC logic for
  phycore_imx8mp.
- Enable watchdog on colibri-imx7.
- Move imx8mm-venice to use OF_UPSTREAM.