nvme-rdma: stop controller reset if the controller is deleting

If the controller is deleting (in case the user decided to delete it), we
have no point to continue reset sequence.

Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>