[NETDEV] config: revert part of previous patch

Net devices should depend on NETDEVICES, so revert part of
Paolo's previous patch.

See http://marc.theaimsgroup.com/?l=linux-kernel&m=115566326218740&w=2
for history.

Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: David S. Miller <davem@davemloft.net>