common/menu.c: Fix build warning

Fix:
menu.c: In function 'menu_item_print':
menu.c:91: warning: passing argument 1 of 'putc' makes integer from
pointer without a cast

Signed-off-by: Anatolij Gustschin <agust@denx.de>
Acked-by: Heiko Schocher <hs@denx.de>
Tested-by: Heiko Schocher <hs@denx.de>
Acked-by: Marek Vasut <marek.vasut@gmail.com>

common/menu.c

@@ -88,7 +88,7 @@ static inline void *menu_item_print(struct menu *m,
 				void *extra)
 {
 	if (!m->item_data_print) {
-		putc(item->key);
+		puts(item->key);
 		putc('\n');
 	} else {
 		m->item_data_print(item->data);