RDMA/hns: Compilation Configuration update

driver inclusion
category: Bugfix
bugzilla: NA
CVE: NA

We updated dfx module related conditional compilation layout to
ensure proper compilation when we turnoff dfx in .config file.

Signed-off-by: Gao Xun <gaoxun3@huawei.com>
Reviewed-by: Hu Chunzhi <huchunzhi@huawei.com>
Reviewed-by: Wang Lin <wanglin137@huawei.com>
Reviewed-by: Zhao Weibo <zhaoweibo3@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>