nvme-fc: don't hold rport lock when putting ctrl

nvme-fc: don't hold rport lock when putting ctrl

nvme_fc_ctrl_put can acquire the rport lock when freeing the
ctrl object:

nvme_fc_ctrl_put
  nvme_fc_ctrl_free
    spin_lock_irqsave(rport->lock)

Thus we can't hold the rport lock when calling nvme_fc_ctrl_put.

Justin suggested use the safe list iterator variant because
nvme_fc_ctrl_put will also modify the rport->list.

Cc: Justin Tee <justin.tee@broadcom.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Daniel Wagner <wagi@kernel.org>
Signed-off-by: Keith Busch <kbusch@kernel.org>