scsi: qla2xxx: Change discovery state before PLOGI

When a port sends PLOGI, discovery state should be changed to login
pending, otherwise RELOGIN_NEEDED bit is set in
qla24xx_handle_plogi_done_event(). RELOGIN_NEEDED triggers another PLOGI,
and it never goes out of the loop until login timer expires.

Fixes: 8777e431 ("scsi: qla2xxx: Migrate NVME N2N handling into state machine")
Fixes: 8b5292bc

 ("scsi: qla2xxx: Fix Relogin to prevent modifying scan_state flag")
Cc: Quinn Tran <qutran@marvell.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20191125165702.1013-6-r.bolshakov@yadro.com
Acked-by: Himanshu Madhani <hmadhani@marvell.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Tested-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Roman Bolshakov <r.bolshakov@yadro.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>