RDMA/i40iw: Fix incorrect iterator type

Commit f27b4746

 ("i40iw: add connection management code") uses an
incorrect rcu iterator, whilst holding the rtnl_lock. Since the
critical region invokes i40iw_manage_qhash(), which is a sleeping
function, the rcu locking and traversal cannot be used.

Signed-off-by: Håkon Bugge <haakon.bugge@oracle.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>