menuconfig: Fix memory leak introduced by jump keys feature

Fixes the memory leak of struct jump_key allocated in get_prompt_str()

Signed-off-by: Benjamin Poirier <bpoirier@suse.de>
Tested-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: stable@vger.kernel.org
diff --git a/scripts/kconfig/list.h b/scripts/kconfig/list.h
index 0ae730b..b87206c 100644
--- a/scripts/kconfig/list.h
+++ b/scripts/kconfig/list.h
@@ -51,6 +51,19 @@
 	     pos = list_entry(pos->member.next, typeof(*pos), member))
 
 /**
+ * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
+ * @pos:	the type * to use as a loop cursor.
+ * @n:		another type * to use as temporary storage
+ * @head:	the head for your list.
+ * @member:	the name of the list_struct within the struct.
+ */
+#define list_for_each_entry_safe(pos, n, head, member)			\
+	for (pos = list_entry((head)->next, typeof(*pos), member),	\
+		n = list_entry(pos->member.next, typeof(*pos), member);	\
+	     &pos->member != (head);					\
+	     pos = n, n = list_entry(n->member.next, typeof(*n), member))
+
+/**
  * list_empty - tests whether a list is empty
  * @head: the list to test.
  */