A list of macros are defined for RSS offload types [1].
They have no descriptions, and some of them have very similar names, so it's
unclear what exactly they mean.

Examples:
- Does RTE_ETH_RSS_IPV4 provide the same RSS offload as (RTE_ETH_RSS_FRAG_IPV4
| RTE_ETH_RSS_NONFRAG_IPV4_OTHER)?
- What does RTE_ETH_RSS_IPV6_EX do, compared to RTE_ETH_RSS_IPV6?

[1]: https://elixir.bootlin.com/dpdk/v25.03/source/lib/ethdev/rte_ethdev.h#L553

Each of these macros should be documented.