text: Remove unused linked list from input_method_context

Signed-off-by: Derek Foreman <derekf@osg.samsung.com>

src/text-backend.c

@@ -82,8 +82,6 @@ struct input_method_context {
 	struct text_input *model;
 	struct input_method *input_method;
 
-	struct wl_list link;
-
 	struct wl_resource *keyboard;
 };