nvme-fc: remove freeze/unfreeze around update_nr_hw_queues

Remove the freeze/unfreeze around changes to the number of hardware
queues. Study and retest has indicated there are no ios that can be
active at this point so there is nothing to freeze.

nvme-fc is draining the queues in the shutdown and error recovery path
in __nvme_fc_abort_outstanding_ios.

This patch primarily reverts 88e837ed

 "nvme-fc: wait for queues to
freeze before calling update_hr_hw_queues". It's not an exact revert as
it leaves the adjusting of hw queues only if the count changes.

Signed-off-by: James Smart <jsmart2021@gmail.com>
[dwagner: added explanation why no IO is pending]
Signed-off-by: Daniel Wagner <dwagner@suse.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>