selftests/bpf: Add mprog API tests for BPF tcx links

jira LE-1907
Rebuild_History Non-Buildable kernel-5.14.0-427.18.1.el9_4
commit-author Daniel Borkmann <[email protected]>
commit c6d479b

Add a big batch of test coverage to assert all aspects of the tcx link API:

  # ./vmtest.sh -- ./test_progs -t tc_links
  [...]
  ctrliq#225     tc_links_after:OK
  ctrliq#226     tc_links_append:OK
  ctrliq#227     tc_links_basic:OK
  ctrliq#228     tc_links_before:OK
  ctrliq#229     tc_links_chain_classic:OK
  ctrliq#230     tc_links_dev_cleanup:OK
  ctrliq#231     tc_links_invalid:OK
  ctrliq#232     tc_links_prepend:OK
  ctrliq#233     tc_links_replace:OK
  ctrliq#234     tc_links_revision:OK
  Summary: 10/0 PASSED, 0 SKIPPED, 0 FAILED

	Signed-off-by: Daniel Borkmann <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
	Signed-off-by: Alexei Starovoitov <[email protected]>
(cherry picked from commit c6d479b)
	Signed-off-by: Jonathan Maple <[email protected]>

Author: PlaidCat