We already could tell the difference in the callback between an import
and "other" which we called interactive. Now add further distinction
between interactive (i.e. running env set / env edit / env ask / etc.
from the U-Boot command line) and programmatic (i.e. when u-boot source
calls any variant of setenv() ).

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
Reviewed-by: Simon Glass <sjg@chromium.org>