The PF and VF rss get APIs are almost the same espect the suffixes of API
names. These same impementions bring double development and bugfix work.

So this patch creates new common rss get APIs for PF and VF rss module.
Subfunctions called by rss query process are also created(e.g. rss tuple
conversion APIs).

These new common rss get APIs will be used to replace PF and VF old rss
APIs in next patches.
Signed-off-by: Jie Wang <wangjie125@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>