scsi: qla2xxx: Decrement login retry count for only plogi

Decrement login retry count only for plogi instead of number of attempts made
for login.

Signed-off-by: Quinn Tran <quinn.tran@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>