net: resolve symbol conflicts with generic hashtable.h
This is a preparatory patch for converting qdisc linked list into a
hashtable. As we'll need to include hashtable.h in netdevice.h, we first
have to make sure that this will not introduce symbol conflicts for any of
the netdevice.h users.
Reviewed-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: David S. Miller <davem@davemloft.net>