trace: trivial fixes in comment typos.

Impact: clean up

Fixed several typos in the comments.

Signed-off-by: Wenji Huang <wenji.huang@oracle.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 7840e71..5e302d6 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -140,7 +140,7 @@
 #endif
 
 /**
- * ftrace_make_nop - convert code into top
+ * ftrace_make_nop - convert code into nop
  * @mod: module structure if called by module load initialization
  * @rec: the mcount call site record
  * @addr: the address that the call site should be calling