selftests/ftrace: Fix typo in trigger-multihist.tc

This patch fix a spelling typo in trigger-multihist.tc
Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

tools/testing/selftests/ftrace/test.d/trigger/trigger-multihist.tc

@@ -23,7 +23,7 @@ if [ ! -f events/sched/sched_process_fork/hist ]; then
     exit_unsupported
 fi
 
-echo "Test histogram multiple tiggers"
+echo "Test histogram multiple triggers"
 
 echo 'hist:keys=parent_pid:vals=child_pid' > events/sched/sched_process_fork/trigger
 echo 'hist:keys=parent_comm:vals=child_pid' >> events/sched/sched_process_fork/trigger