scsi: mpt3sas: Don't access the structure after decrementing it's instance reference count.

While configuring of NVMe device handling, _pcie_device structure member
was accessed after its reference count is decremented/put. Hence modified
code to access member of _pcie_device structure before its reference count
is decremented/put.

Signed-off-by: Chaitra P B <chaitra.basappa@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>