ethdev: flatten RSS configuration in flow API

ethdev: flatten RSS configuration in flow API

Since its inception, the rte_flow RSS action has been relying in part on
external struct rte_eth_rss_conf for compatibility with the legacy RSS API.
This structure lacks parameters such as the hash algorithm to use, and more
recently, a method to tell which layer RSS should be performed on [1].

Given struct rte_eth_rss_conf will never be flexible enough to represent a
complete RSS configuration (e.g. RETA table), this patch supersedes it by
extending the rte_flow RSS action directly.

A subsequent patch will add a field to use a non-default RSS hash
algorithm. To that end, a field named "types" replaces the field formerly
known as "rss_hf" and standing for "RSS hash functions" as it was
confusing. Actual RSS hash function types are defined by enum
rte_eth_hash_function.

This patch updates all PMDs and example applications accordingly.

It breaks ABI compatibility for the following public functions:

- rte_flow_copy()
- rte_flow_create()
- rte_flow_query()
- rte_flow_validate()

[1] commit 676b605182a5 ("doc: announce ethdev API change for RSS
    configuration")

Signed-off-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>
Acked-by: Andrew Rybchenko <arybchenko@solarflare.com>