linux-imx

bpf: use libbpf_num_possible_cpus internally

Use the newly added bpf_num_possible_cpus() in bpftool and selftests
and remove duplicate implementations.

Signed-off-by: Hechao Li <hechaol@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>