selftests: net: reuseport_bpf_numa: don't fail if no numa support

The reuseport_bpf_numa test case fails there's no numa support.  The
test shouldn't fail if there's no support it should be skipped.

Fixes: 3c2c3c16

 ("reuseport, bpf: add test case for bpf_get_numa_node_id")
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>