Fix some typo for include folder

Signed-off-by: Wenxing Hou <wenxing.hou@intel.com>
diff --git a/programs/test/metatest.c b/programs/test/metatest.c
index c52e579..75829ec 100644
--- a/programs/test/metatest.c
+++ b/programs/test/metatest.c
@@ -381,7 +381,7 @@
     void (*entry_point)(const char *name);
 } metatest_t;
 
-/* The list of availble meta-tests. Remember to register new functions here!
+/* The list of available meta-tests. Remember to register new functions here!
  *
  * Note that we always compile all the functions, so that `metatest --list`
  * will always list all the available meta-tests.