qla2xxx: Add flush after updating ATIOQ consumer index.

After updating the consumer index of ATIO Q, a read is
required to flush the write to the adapter register.

Signed-off-by: Quinn Tran <quinn.tran@qlogic.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@qlogic.com>
Reviewed-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/scsi/qla2xxx/qla_target.c

@@ -5546,6 +5546,7 @@ qlt_24xx_process_atio_queue(struct scsi_qla_host *vha)
 
 	/* Adjust ring index */
 	WRT_REG_DWORD(ISP_ATIO_Q_OUT(vha), ha->tgt.atio_ring_index);
+	RD_REG_DWORD_RELAXED(ISP_ATIO_Q_OUT(vha));
 }
 
 void