U-Boot 2022.10: Backport patches for Kontron i.MX6UL/ULL config

This MR is similar to !20 (merged) for the i.MX8MM boards.

This adds upstream patches for the Kontron i.MX6UL/ULL boards to the v2022.10 branch.
All patches in this MR except for one have already been reviewed upstream: https://source.denx.de/u-boot/u-boot/-/commits/master?search=frieder.

This solves the i.MX6UL part of https://git.kontron-electronics.de/sw/ked/plan/plan-yocto/-/issues/952.

CC: @Maximilian

Todo:

• Test A/B boot from SPI NOR and SPI NAND with SWUpdate
• Create MR for required changes in meta-ktn-imx (sw/yocto/meta-ktn-imx!46 (merged))
  • Switch to 2022.10

Incompatible Changes (v2020.01-ktn)

• SPI NOR Layout:
  • One partition for SPL + U-Boot, U-Boot now generates single flash.bin file for both.