bpf: move BPF_F_QUERY_EFFECTIVE after map flags

BPF_F_QUERY_EFFECTIVE is in the middle of the flags valid
for BPF_MAP_CREATE. Move it to its own section to reduce confusion.

Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>