samples/bpf: Add openat2() enter/exit tracepoint to syscall_tp sample

Commit fe330089("samples: bpf: fix syscall_tp due to unused syscall")
added openat() syscall tracepoints. This patch adds support for
openat2() as well.
Signed-off-by: Rong Tao <rongtao@cestc.cn>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/tencent_9381CB1A158ED7ADD12C4406034E21A3AC07@qq.com

samples/bpf/syscall_tp_kern.c

@@ -58,6 +58,13 @@ int trace_enter_open_at(struct syscalls_enter_open_args *ctx)
 	return 0;
 }
 
+SEC("tracepoint/syscalls/sys_enter_openat2")
+int trace_enter_open_at2(struct syscalls_enter_open_args *ctx)
+{
+	count(&enter_open_map);
+	return 0;
+}
+
 SEC("tracepoint/syscalls/sys_exit_open")
 int trace_enter_exit(struct syscalls_exit_open_args *ctx)
 {
@@ -71,3 +78,10 @@ int trace_enter_exit_at(struct syscalls_exit_open_args *ctx)
 	count(&exit_open_map);
 	return 0;
 }
+
+SEC("tracepoint/syscalls/sys_exit_openat2")
+int trace_enter_exit_at2(struct syscalls_exit_open_args *ctx)
+{
+	count(&exit_open_map);
+	return 0;
+}