update/add missing AF_XDP structs & constants

[arctic-alpaca]

Description

This PR adds missing structs/constants from the if_xdp.h header and updates the xdp_umem_reg struct. Due to the added field in xdp_umem_reg, this is a breaking change from the 0.2 branch.

Ideally, I would like to include all the changes in the 0.2 branch. Would it be possible to add a xdp_umem_reg_v3 to not break the current xdp_umem_reg?
If not, how would deprecating a struct to change it work? Just add a deprecation notice, wait for X amount of time, add the field?

Sources

AF_XDP documentation: https://docs.kernel.org/networking/af_xdp.html
Header file: https://github.com/torvalds/linux/blob/v6.11/include/uapi/linux/if_xdp.h

Checklist

• Relevant tests in libc-test/semver have been updated
• No placeholder or unstable values like *LAST or *MAX are
  included (see #3131)
• Tested locally (cd libc-test && cargo test --target mytarget);
  especially relevant for platforms that may not be checked in CI

I could not test the the changes locally due to the error described in #3865 (comment)

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