[SCSI] qla2xxx: fix potential deadlock on ha->hardware_lock

Lockdep reports:

=== [ cut here ] ===
 =========================================================
 [ INFO: possible irq lock inversion dependency detected ]
 3.6.0-0.0.0.28.36b5ec9-default #1 Not tainted
 ---------------------------------------------------------
 qla2xxx_1_dpc/368 just changed the state of lock:
  (&(&ha->vport_slock)->rlock){+.....}, at: [<ffffffffa009b377>] qla2x00_configure_hba+0x197/0x3c0 [qla2xxx]
 but this lock was taken by another, HARDIRQ-safe lock in the past:
  (&(&ha->hardware_lock)->rlock){-.....}

and interrupts could create inverse lock ordering between them.

other info that might help us debug this:
 Possible interrupt unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&(&ha->vport_slock)->rlock);
                               local_irq_disable();
                               lock(&(&ha->hardware_lock)->rlock);
                               lock(&(&ha->vport_slock)->rlock);
  <Interrupt>
    lock(&(&ha->hardware_lock)->rlock);
=== [ cut here ] ===

Fix the potential deadlock by disabling IRQs while holding ha->vport_slock.
Reported-and-tested-by: NSrivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>
Acked-by: NSaurav Kashyap <saurav.kashyap@qlogic.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

drivers/scsi/qla2xxx/qla_init.c

@@ -2080,6 +2080,7 @@ qla2x00_configure_hba(scsi_qla_host_t *vha)
 	uint8_t       domain;
 	char		connect_type[22];
 	struct qla_hw_data *ha = vha->hw;
+	unsigned long flags;
 
 	/* Get host addresses. */
 	rval = qla2x00_get_adapter_id(vha,
@@ -2154,9 +2155,9 @@ qla2x00_configure_hba(scsi_qla_host_t *vha)
 	vha->d_id.b.area = area;
 	vha->d_id.b.al_pa = al_pa;
 
-	spin_lock(&ha->vport_slock);
+	spin_lock_irqsave(&ha->vport_slock, flags);
 	qlt_update_vp_map(vha, SET_AL_PA);
-	spin_unlock(&ha->vport_slock);
+	spin_unlock_irqrestore(&ha->vport_slock, flags);
 
 	if (!vha->flags.init_done)
 		ql_log(ql_log_info, vha, 0x2010,