yanglint BUGFIX features option fixes

The description was improved and should
now finally be 100% correct and either
no features are specified, when all
are enabled or if some are specified,
only those are enabled and no others.
diff --git a/tools/lint/common.c b/tools/lint/common.c
index d319410..5c5894e 100644
--- a/tools/lint/common.c
+++ b/tools/lint/common.c
@@ -108,8 +108,6 @@
 void
 get_features(struct ly_set *fset, const char *module, const char ***features)
 {
-    static const char *all_features[] = {"*", NULL};
-
     /* get features list for this module */
     for (uint32_t u = 0; u < fset->count; ++u) {
         struct schema_features *sf = (struct schema_features *)fset->objs[u];
@@ -120,8 +118,8 @@
         }
     }
 
-    /* features not set, enable all features by default */
-    *features = all_features;
+    /* features not set so disable all */
+    *features = NULL;
 }
 
 int