scsi: libfc: Return LS_RJT_BUSY for PRLI in status PLOGI

Occasionally it might happen that we receive a PRLI while we're still
waiting for our PLOGI response. In that case we should return
'busy' LS status instead of 'plogi required' LS status.

Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>