lib/list: Add list_append

This method will add a node to the end of the list.

BUG=b:179699789
TEST=Boot guybrush to the OS

Signed-off-by: Raul E Rangel <rrangel@chromium.org>
Change-Id: I1792e40f789e3ef16ceca65ce4cae946e08583d1
Reviewed-on: https://review.coreboot.org/c/coreboot/+/58805
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>

src/lib/list.c

@@ -28,3 +28,11 @@ void list_insert_before(struct list_node *node, struct list_node *before)
 	if (node->prev)
 		node->prev->next = node;
 }
+
+void list_append(struct list_node *node, struct list_node *head)
+{
+	while (head->next)
+		head = head->next;
+
+	list_insert_after(node, head);
+}