bpf: add a test case for helper bpf_perf_prog_read_value

The bpf sample program trace_event is enhanced to use the new
helper to print out enabled/running time.

Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Alexei Starovoitov <ast@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/include/uapi/linux/bpf.h

@@ -698,7 +698,8 @@ union bpf_attr {
 	FN(sk_redirect_map),		\
 	FN(sock_map_update),		\
 	FN(xdp_adjust_meta),		\
-	FN(perf_event_read_value),
+	FN(perf_event_read_value),	\
+	FN(perf_prog_read_value),
 
 /* integer value in 'imm' field of BPF_CALL instruction selects which helper
  * function eBPF program intends to call