scsi: libsas: delete sas port out of the disco mutex

driver inclusion
category: bugfix
bugzilla: NA
CVE: NA

delete sas port out of the disco mutex

Signed-off-by: Jason Yan <yanaijie@huawei.com>

Feature or Bugfix:Bugfix

Signed-off-by: luojiaxing <luojiaxing@huawei.com>
Reviewed-by: chenxiang <chenxiang66@hisilicon.com>
Reviewed-by: Xie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>