config: use SCSI_MQ by default

euler inclusion
category: bugfix
bugzilla: 5479
CVE: NA

After 4.19, SCSI_MQ is enabled by default in mainline, and the code of
SQ is removed from linux 5.0. So we use MQ by default.

Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>