tree should not return a result when we pass an empty string

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
diff --git a/tree.c b/tree.c
index f95610a..aefe0fe 100644
--- a/tree.c
+++ b/tree.c
@@ -304,6 +304,9 @@
 {
 	struct struct_find *sf = data;
 
+	if (!strlen(sf->name))
+		return 0;
+
 	if (strncmp(sf->name, tree->name, strlen(sf->name)))
 		return 0;