There are two u-boot targets which should work with the sabre lite
boards. mx6qsabrelite (which sets fdt_addr) and nitrogen6q
(which sets fdtaddr). The difference seems to be the mx6qsabrelite
target uses a small loader in SPI connected flash which will load
the rest of u-boot from an SD card. The nitrogen6q target normally
loads all of u-boot from an image in flash and then searches for a
6x_bootscript file with u-boot commands on MMC and SATA.

While neither of them supports "Generic Distro Configuration" which
would automatically search for an EFI image, if they did fdt_addr
is intended to be used for a DTB in ROM, while fdt_addr_r is intended
to be used for a DTB in RAM.

Change the 6x_bootscript u-boot commands to load the DTB to
fdtaddr instead of fdt_addr as matthieu@ reported fdt_addr was not
present in the u-boot environment on his system.

Mainline u-boot on SABRE Lite/BD-SL-i.MX6 does not have the generic
distro hooks that automatically load an efi file if found.

Instead it looks for a '6x_bootscript' u-boot script as the original
boundary devices u-boot did.

Create a script in the nitrogen miniroot and on install that will
load a dtb and bootarm.efi then call bootefi. Based on notes
from matthieu@

use a simple u-boot script for all the miniroots that loads with fdt
ok patrick@ kettenis@