kernel/device_manager: don't insert device node before nodes of the same priority

fix #16512

Change-Id: I76ce4cfc9346492008c11ca53302ca4df6a6b514
Reviewed-on: https://review.haiku-os.org/c/haiku/+/5393
Reviewed-by: Adrien Destugues <pulkomandy@pulkomandy.tk>

src/system/kernel/device_manager/device_manager.cpp

@@ -1454,7 +1454,7 @@ device_node::AddChild(device_node* node)
 	device_node* before = NULL;
 	while (iterator.HasNext()) {
 		device_node* child = iterator.Next();
-		if (child->Priority() <= priority) {
+		if (child->Priority() < priority) {
 			before = child;
 			break;
 		}