scripts: kconfigfunctions: add a comment

I can never remember what the contents of the kconfigfunctions dict is
and have to look it up every time. I suspect I'm not alone, and not
everyone who uses these will know how to look up the answer. Add a
comment explaining the value.

Signed-off-by: Martí Bolívar <marti.bolivar@nordicsemi.no>
1 file changed