Fix typo

Signed-off-by: Pengyu Lv <pengyu.lv@arm.com>
diff --git a/tests/compat.sh b/tests/compat.sh
index e520c31..e7f9d49 100755
--- a/tests/compat.sh
+++ b/tests/compat.sh
@@ -1175,7 +1175,7 @@
             if [ $EXIT -eq 0 ]; then
                 RESULT=0
             else
-                # If ti is NULL cipher ...
+                # If it is NULL cipher ...
                 if grep 'Cipher is (NONE)' $CLI_OUT >/dev/null; then
                     RESULT=1
                 else