netcf: hardcode --with-driver=redhat for target build

The configure script of netcf checks the HOST setup to identify the
network interface. This means it checks for Red Hat, SuSE, debian,
Ubuntu, etc. As this is an embedded cross build, it doesn't seem to
make sense to check the HOST in the first place to determine info for
the TARGET.

Signed-off-by: Ting Liu <b28495@freescale.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>