Commit f2c31e32 ("net: fix NULL dereferences in check_peer_redir()")
forgot to take care of infiniband uses of dst neighbours.

Many thanks to Marc Aurele who provided a nice bug report and feedback.
Reported-by: NMarc Aurele La France <tsi@ualberta.ca>
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Cc: David Miller <davem@davemloft.net>
Cc: <stable@kernel.org>
Signed-off-by: NRoland Dreier <roland@purestorage.com>