linux-5.10.y: please backport to fix BPF selftest breakage

[Lorenz Bauer <lmb@xxxxxxxxxxxxx>]

Hi stable team,

Building BPF selftests on 5.10.186 currently causes the following compile error:

$ make -C tools/testing/selftests/bpf
...
  BINARY   test_verifier
In file included from
/usr/src/linux-5.10.186/tools/testing/selftests/bpf/verifier/tests.h:59,
                 from test_verifier.c:355:
/usr/src/linux-5.10.186/tools/testing/selftests/bpf/verifier/ref_tracking.c:935:10:
error: 'struct bpf_test' has no member named 'fixup_map_ringbuf'; did
you mean 'fixup_map_in_map'?
  935 |         .fixup_map_ringbuf = { 11 },
      |          ^~~~~~~~~~~~~~~~~
      |          fixup_map_in_map

The problem was introduced by commit f4b8c0710ab6 ("selftests/bpf: Add
verifier test for release_reference()") in your tree.

Seems like at least commit 4237e9f4a962 ("selftests/bpf: Add verifier
test for PTR_TO_MEM spill") is required for the build to succeed.

I previously reported this but things probably fell through the
cracks: https://lore.kernel.org/stable/CAN+4W8iMcwwVjmSekZ9txzZNxOZ0x98nBXo4cEoTU9G2zLe8HA@xxxxxxxxxxxxxx/#t

Thanks!
Lorenz