U-Boot 2022.10 for Kontron i.MX8MM boards to sync with upstream

This MR is the follow-up of !16 (closed).

This adds pending upstream patches for the Kontron i.MX8MM boards to the v2022.10 branch.
All patches in this MR have already been reviewed upstream: https://source.denx.de/u-boot/custodians/u-boot-imx/-/commits/master?search=frieder.

This intends to cover the requirements in https://git.kontron-electronics.de/sw/ked/plan/plan-yocto/-/issues/943#note_29986.

CC: @Maximilian

Todo:

• Test A/B boot from SPI NOR and eMMC with SWUpdate
• Test on non-OSM and OSM boards
• Update with feedback from mailing list
• Create MR for required changes in meta-ktn-imx (sw/yocto/meta-ktn-imx!35 (merged))
  • Remove unused 2021.07 recipes
  • Switch to 2022.10
• Optional: Test standard distro boot
• Find a way to have a single environment for standard distro boot and SWUpdate A/B boot
• Update to v2022.10

Incompatible Changes (v2020.01-ktn)

• SPI NOR Layout:
  • One partition for SPL + U-Boot, U-Boot now generates single flash.bin file for both.
  • Move environment to end of NOR flash, otherwise the U-Boot binary might collide with the env when it gets bigger.
• MMC Layout:
  • Offset of U-Boot proper is defined by bootloader (binman config) and is now 0x300 (512 bytes sectors) instead of 0x800.
    This is now a default used by other i.MX8MM boards. The SPI NOR offset (CONFIG_SYS_SPI_U_BOOT_OFFS) was adjusted to match this layout. Therefore flash.bin can be used for MMC and SPI NOR.

Changelog

Changes from version 1 to version 2

• Remove last patch with custom environment, we will overwrite the environment from Yocto if necessary.

Changes from version 3 (old MR !16 (closed)) to version 1 (this MR)

• Rebase on develop-v2022.10-ktn-imx and drop backported patches
• Update Patches to match upstream submission (add renaming of devicetree files, etc.)
• Adjust patch for custom/vendor boot flow in environment to preserve distro boot flow as option

Changes from version 2 to 3 (old MR !16 (closed))

• Rebase on current develop-v2022.07-ktn-imx with backported patches already merged (!18 (merged))

Changes from version 1 to 2 (old MR !16 (closed))

• Add backported patches to shrink SPL binary size
• Enable SPI NOR loading in SPL which was accidentally dropped upstream
• Add SPI NOR partition layout to devicetree
• Add simple netboot to environment
• Fix environment scripts for A/B boot
• Remove custom board_boot_order() workaround
• Add MTD command
• Increase U-Boot shell max line length (CONFIG_SYS_CBSIZE)