IB/ipoib: Fix inconsistency with free_netdev and free_rdma_netdev

Call free_rdma_netdev instead of free_netdev each time we want to
release a netdevice. This call is also relevant for future freeing
of offloaded child interfaces.

This patch also adds a missing call for free netdevice when releasing
a parent interface that has child interfaces using ipoib_remove_one.

Fixes: cd565b4b

 ('IB/IPoIB: Support acceleration options callbacks')
Signed-off-by: Alex Vesker <valex@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>