scsi: lpfc: Fix panic if driver unloaded when port is offline

System crashes when the lpfc module is unloaded after making the port
offline

The nvme queue pointers were freed during port offline, but were later
accessed in pci remove path.

Validate the pointers in pci remove path before accessing them.

Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <james.smart@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>