nvme: Move nvme_freeze/unfreeze_queues to nvme core

nvme: Move nvme_freeze/unfreeze_queues to nvme core

Nothing pci specific about them and We'll need them exported
in other transports too.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
(cherry picked from commit 363c9aacb6c59bb63148dd115632880a4aed4d88)

Orabug: 25130845

Signed-off-by: Ashok Vairavan <ashok.vairavan@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>