scsi: libiscsi: Remove unnecessary memset() in iscsi_conn_setup()

iscsi_cls_conn is alloced by kzalloc(), the whole iscsi_cls_conn is zero
filled already including the dd_data. So it is unnecessary to call memset
again.

Link: https://lore.kernel.org/r/20220317150116.194140-1-haowenchao@huawei.com


Reviewed-by: Wu Bo <wubo40@huawei.com>
Reviewed-by: Lee Duncan <lduncan@suse.com>
Reviewed-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Wenchao Hao <haowenchao@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>