Add cli_ prefix to readline functions

This makes it clear where the code resides.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/common/menu.c b/common/menu.c
index 88d4697..94afeb2 100644
--- a/common/menu.c
+++ b/common/menu.c
@@ -197,8 +197,9 @@
 		menu_display(m);
 
 		if (!m->item_choice) {
-			readret = readline_into_buffer("Enter choice: ", cbuf,
-					m->timeout / 10);
+			readret = cli_readline_into_buffer("Enter choice: ",
+							   cbuf,
+							   m->timeout / 10);
 
 			if (readret >= 0) {
 				choice_item = menu_item_by_key(m, cbuf);