data MAINTENANCE improve code readability

Do not check for presence of data which were already checked
diff --git a/src/tree_data.c b/src/tree_data.c
index d539a5a..4a8d5e9 100644
--- a/src/tree_data.c
+++ b/src/tree_data.c
@@ -987,9 +987,8 @@
     if (rc) {
         lyd_free_tree(ret);
         ret = NULL;
-    } else if (node) {
-        *node = ret;
     }
+    *node = ret;
     return rc;
 }