nvmet-rdma: removed queue cleanup from module exit

We already do that when we are notified in device removal
which is triggered when unregistering as an ib client.

Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Max Gurtovoy <maxg@mellanox.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>