net: fix up a few missing hashtable.h conflict resolutions

There are a couple of leftover symbol conflicts caused by hashtable.h
being included by netdevice.h; those were not caught as build failure
(they're "only" a warning, but in fact real bugs). Fix those up.

Fixes: e87a8f24

 ("net: resolve symbol conflicts with generic hashtable.h")
Reported-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>