scsi: qla2xxx: Allow NVMe IO to resume with short cable pull

Current driver report dev_loss_tmo to 0 for NVMe devices with short cable
pull.  This causes NVMe controller to be freed along with NVMe namespace.
The side affect is IO would stop.  By not setting dev_loss_tmo to 0, NVMe
namespace would stay until cable is plugged back in.  This allows IO to
resume afterward.

[mkp: commit desc]

Signed-off-by: Arun Easi <aeasi@marvell.com>
Signed-off-by: Quinn Tran <qutran@marvell.com>
Signed-off-by: Himanshu Madhani <hmadhani@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>