Integrate meta-guf-distro/add_libubootenv

Commit: https://gitlab.com/garz-fricke/yocto/layers/meta-guf-distro/-/commit/8fe960b95d6a803f6666873a77c9fdf9613926d6

imx8m:libubootenv: Add libubootenv and userspace U-Boot tools

The iMX8M uses U-Boot as bootloader. The libubootenv provides means to access the U-Boot environments from the user-space of the Linux OS.

Add libubootenv and the binaries fw_printenv and fw_setenv as well as the current TANARO u-boot environment settings.

Try to figure out if U-Boot is the used bootloader by checking for existence of the variables UBOOT_CONFIG and UBOOT_MACHINE.

BCS 746-000356