selftests: bpf: Adding config fragment CONFIG_CGROUP_BPF=y

CONFIG_CGROUP_BPF=y is required for test_dev_cgroup test case.
Signed-off-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

tools/testing/selftests/bpf/config

@@ -3,3 +3,4 @@ CONFIG_BPF_SYSCALL=y
 CONFIG_NET_CLS_BPF=m
 CONFIG_BPF_EVENTS=y
 CONFIG_TEST_BPF=m
+CONFIG_CGROUP_BPF=y