selftests/bpf: add config fragment CONFIG_FTRACE_SYSCALLS

CONFIG_FTRACE_SYSCALLS=y is required for get_cgroup_id_user test case
this test reads a file from debug trace path
/sys/kernel/debug/tracing/events/syscalls/sys_enter_nanosleep/id
Signed-off-by: NNaresh Kamboju <naresh.kamboju@linaro.org>
Acked-by: NYonghong Song <yhs@fb.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>

tools/testing/selftests/bpf/config

@@ -22,3 +22,4 @@ CONFIG_NET_CLS_FLOWER=m
 CONFIG_LWTUNNEL=y
 CONFIG_BPF_STREAM_PARSER=y
 CONFIG_XDP_SOCKETS=y
+CONFIG_FTRACE_SYSCALLS=y