Merge patch series "board/ti: k3 boards: Stop using findfdt"

Nishanth Menon <nm@ti.com> says:

This is a wide cleanup to switch to setting fdtfile using env_set
instead of scripted magic. 'fdtfile' is expected to be set by default.
This allows the stdboot triggered efi loaders to find the correct OS
device tree file even if regular boot process is interrupted by user
intervention.

This is a refresh of
https://lore.kernel.org/all/86le9dwz4d.fsf@udb0321960.dhcp.ti.com/ which
was the wrong approach.

Updates from V1:
 * Renames of variables and macros for various review comments.
 * Commit message updates in some patches for clarity.

Bootlogs: https://gist.github.com/nmenon/843e343cde645ec4aa57b60cece5256a

based on master: c5e461fb Merge tag 'u-boot-imx-master-20240108' of https://gitlab.denx.de/u-boot/custodians/u-boot-imx

NOTE: There are a couple of checkpatch WARN (around LATE_INIT) and
CHECK (fdt_ops #ifdeffery) that on closer inspection looks fine and
consistent with other similar usage.