selftests/ftrace: Fix same probe error test

The "same probe" selftest that tests that adding the same probe fails
doesn't add the same probe and passes, which fails the test.

Fixes: b78b94b8 ("selftests/ftrace: Update kprobe event error testcase")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

tools/testing/selftests/ftrace/test.d/kprobe/kprobe_syntax_errors.tc

@@ -95,7 +95,7 @@ echo 'p:kprobes/testevent _do_fork abcd=\1' > kprobe_events
 check_error 'p:kprobes/testevent _do_fork ^bcd=\1'	# DIFF_ARG_TYPE
 check_error 'p:kprobes/testevent _do_fork ^abcd=\1:u8'	# DIFF_ARG_TYPE
 check_error 'p:kprobes/testevent _do_fork ^abcd=\"foo"'	# DIFF_ARG_TYPE
-check_error '^p:kprobes/testevent _do_fork'	# SAME_PROBE
+check_error '^p:kprobes/testevent _do_fork abcd=\1'	# SAME_PROBE
 fi
 
 exit 0