buildroot

Remove ConfigFS from Busybox skeleton

It is not included in generic skeleton and very unlikely
that someone will use it on embedded devices.
AFAIK even Fedora does not include it in fstab.

Signed-off-by: Paulius Zaleckas <paulius.zaleckas@gmail.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>