Provide /etc/fw_env.config to allow getting/setting u-boot environment from OS
The fw_printenv(8) and fw_setenv(8) programs in the u-boot-tools package require a configuration file, /etc/fw_env.config, to work. Various examples are under /usr/share/doc/u-boot-tools/examples and here:
https://salsa.debian.org/debian/u-boot/tree/master/debian/env-configs
https://salsa.debian.org/debian/u-boot/blob/master/tools/env/fw_env.config