scsi: qla2xxx: Allow PLOGI in target mode

scsi: qla2xxx: Allow PLOGI in target mode

According to FC-LS-3 (Fibre Channel Link Services) 6.3.2.4
"N_Port Login - No Fabric present", if both parties in the point-to-point
connection know N_Port_Names of each other, Nx_Port with the highest
N_Port_name shall transmit PLOGI. The specification sets no restrictions on
the port role that should send PLOGI.

However, FCP-4 (Fibre Channel Protocol for SCSI, Fourth Version) 6.2
"Overview of Process Login and Process Logout", instructs that in
point-to-point topology, initiator shall send explicit PRLI ELS.

The change fixes stuck P2P login, when target WWPN is higher than initiator
WWPN.

Cc: Quinn Tran <qutran@marvell.com>
Cc: Himanshu Madhani <hmadhani@marvell.com>
Link: https://lore.kernel.org/r/20191125165702.1013-7-r.bolshakov@yadro.com
Signed-off-by: Roman Bolshakov <r.bolshakov@yadro.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>