tracing: fix typos in comments

Impact: clean up.

Fix typos in the comments.

Signed-off-by: Wenji Huang <wenji.huang@oracle.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index d898212..d7c175a 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1963,7 +1963,7 @@
 	struct tracer_opt *trace_opts = current_trace->flags->opts;
 
 
-	/* calulate max size */
+	/* calculate max size */
 	for (i = 0; trace_options[i]; i++) {
 		len += strlen(trace_options[i]);
 		len += 3; /* "no" and space */