package/util-linux: disable libsmartcols in no-MMU platforms

As reported by Thomas Petazzoni [1], the libsmartcols library can't
be used on no-MMU platform since fork() is used.

[1] http://lists.busybox.net/pipermail/buildroot/2016-February/153414.html



Signed-off-by: Romain Naour <romain.naour@gmail.com>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>