Merge tag 'u-boot-imx-master-20241018a' of https://gitlab.denx.de/u-boot/custodians/u-boot-imx

CI: https://source.denx.de/u-boot/custodians/u-boot-imx/-/pipelines/22796

- Switch to using upstream DT on DH i.MX8MP DHCOM PDK2/PDK3.
- Add ability to build fallback DTBOs from arch/$(ARCH)/dts.
- Remove fdt_high and initrd_high env variables from imx6-dhcom.
- Add dummy clk for imx8.
- Fix DT corruption in imx8_cpu.
- Improve DDR stability on pico-imx7d.