selftests/bpf: Use bpf_core_enum_value for stats in cgroup_iter_memcg

Replace hardcoded enum values with bpf_core_enum_value() calls in
cgroup_iter_memcg test to improve portability across different
kernel versions.

The change adds runtime enum value resolution for:
- node_stat_item: NR_ANON_MAPPED, NR_SHMEM, NR_FILE_PAGES,
  NR_FILE_MAPPED
- vm_event_item: PGFAULT

This ensures the BPF program can adapt to enum value changes
between kernel versions.

Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Reviewed-by: JP Kobryn <jp.kobryn@linux.dev>
Signed-off-by: Hui Zhu <zhuhui@kylinos.cn>
Link: https://lore.kernel.org/r/ca6eb1a1a4fd7a17ffe995acf52c9a4ceb7bac13.1772505399.git.zhuhui@kylinos.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

0 files changed, 0 insertions, 0 deletions