scsi: qla2xxx: Do not corrupt vha->plogi_ack_list

Delete the PLOGIN ACK data structure from the vha->plogi_ack_list before
freeing that data structure to avoid that that list gets corrupted.

Cc: Himanshu Madhani <hmadhani@marvell.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Tested-by: Himanshu Madhani <hmadhani@marvell.com>
Reviewed-by: Himanshu Madhani <hmadhani@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>