boot: Keep track of which bootmeths have been used

Add a bitfield which tracks when bootmeths have been used. This will be
needed when global bootmeths can be used later in the iteration.

Fix a missing bootflow_free() while here.

Signed-off-by: Simon Glass <sjg@chromium.org>

boot/bootmeth-uclass.c

@@ -199,6 +199,16 @@ int bootmeth_setup_iter_order(struct bootflow_iter *iter, bool include_global)
 		iter->doing_global = true;
 		iter->have_global = true;
 	}
+
+	/*
+	 * check we don't exceed the maximum bits in methods_done when tracking
+	 * which global bootmeths have run
+	 */
+	if (IS_ENABLED(CONFIG_BOOTMETH_GLOBAL) && count > BOOTMETH_MAX_COUNT) {
+		free(order);
+		return log_msg_ret("tmb", -ENOSPC);
+	}
+
 	iter->method_order = order;
 	iter->num_methods = count;