perf trace: Do not accept --no-syscalls together with -e

Doesn't make sense and was causing a segfault, fix it.

  # trace -e clone --no-syscalls --event sched:*exec firefox
  The -e option can't be used with --no-syscalls.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Milian Wolff <milian.wolff@kdab.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-ccrahezikdk2uebptzr1eyyi@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-trace.c

@@ -3344,6 +3344,8 @@ int cmd_trace(int argc, const char **argv, const char *prefix __maybe_unused)
 		goto out;
 	}
 
+	err = -1;
+
 	if (trace.trace_pgfaults) {
 		trace.opts.sample_address = true;
 		trace.opts.sample_time = true;
@@ -3368,6 +3370,11 @@ int cmd_trace(int argc, const char **argv, const char *prefix __maybe_unused)
 		return -1;
 	}
 
+	if (!trace.trace_syscalls && ev_qualifier_str) {
+		pr_err("The -e option can't be used with --no-syscalls.\n");
+		goto out;
+	}
+
 	if (output_name != NULL) {
 		err = trace__open_output(&trace, output_name);
 		if (err < 0) {