net/tap: rewrite RSS BPF program

Rewrite of the BPF program used to do queue based RSS.
Important changes:
- uses newer BPF map format BTF
- accepts key as parameter rather than constant default

net/tap: rewrite RSS BPF program

Rewrite of the BPF program used to do queue based RSS.
Important changes:
- uses newer BPF map format BTF
- accepts key as parameter rather than constant default
- can do L3 or L4 hashing
- supports IPv4 options
- supports IPv6 extension headers
- restructured for readability

The usage of BPF is different as well:
- the incoming configuration is looked up based on
class parameters rather than patching the BPF code.
- the resulting queue is placed in skb by using skb mark
than requiring a second pass through classifier step.

Note: This version only works with later patch to enable it on
the DPDK driver side. It is submitted as an incremental patch
to allow for easier review. Bisection still works because
the old instruction are still present for now.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Acked-by: Ferruh Yigit <ferruh.yigit@amd.com>

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