Merge tag 'u-boot-imx-master-20240405' of https://gitlab.denx.de/u-boot/custodians/u-boot-imx

CI: https://source.denx.de/u-boot/custodians/u-boot-imx/-/pipelines/20228

- Convert imx8mp-beacon and verdin-imx8mm/verdin-imx8mp to OF_UPSTREAM.
- Enable PCIe NVMe support on imx8mp_beacon.
- Fix Ethernet and board detection on mx6cuboxi.
- Fix signature_block_hdr struct fields.
- Fix imx9_probe_mu prototype and make it to get called in
  EVT_DM_POST_INIT_R.
- Test whether ethernet node is enabled before reading MAC EEPROM on
  DHSOM SoMs.