Usage of fdt_addr vs fdt_addr_r

[Wadim Egorov]

Hi,

there are multiple definitions of fdt_addr and fdt_addr_r:

usage/environment.rst:
Tells us fdt_addr is in flash location and _r in RAM

develop/distro.rst:
fdt_addr -> Mandatory for any system that provides the DTB in HW (e.g. ROM)

I also noticed that bootmeth_efi.c/distro_efi_try_bootflow_files() will 
copy the dtb it has found into fdt_addr_r. But efi_install_fdt() try to 
load first from fdt_addr. Shouldn't they use the same environment variable?

Doing so would allow efiboot to use the dtb it has detected using 
bootflow. Right now it seems to fallback to fdtcontroladdr.

Regards,
Wadim