whenever a node has already a child, it means a driver has already attached to this node

for this reason, we don't add such a node in the list of nodes to be scanned
this fixes the bug #1578


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@22726 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/system/kernel/device_manager/probe.cpp

@@ -983,7 +983,7 @@ get_nodes_for_device_type(device_node_info *node, struct list *list, const char
 			matches = true;
 	}
 
-	if (matches) {
+	if (matches && list_get_first_item(&node->children) == NULL) {
 #ifdef TRACE_PROBE
 		dprintf("** NODE MATCHES TYPE %s\n", type);
 		dm_dump_node(node, 0);