env: CONFIG_DEFAULT_ENV_FILE and CFG_EXTRA_ENV_SETTINGS

[Tony Dinh]

Hi Tom,

I'm trying to move some envs from a board header file to the default
env file. I recall that the envs in CONFIG_DEFAULT_ENV_FILE are
appended to the envs in CFG_EXTRA_ENV_SETTINGS. As you mentioned here
before:

https://lore.kernel.org/all/20220810170439.GJ1146598@bill-the-cat/

But it looks like envs in CFG_EXTRA_ENV_SETTINGS are completely
erased, and then the envs are populated with what's in
CONFIG_DEFAULT_ENV_FILE.

Did I understand the usage correctly?

Thanks,
Tony