iw: Fix regression in mesh_param input parsing

In the iw tool, don't crash on bad arguments to "iw dev mesh set mesh_param"
diff --git a/mesh.c b/mesh.c
index d6edf3f..f663363 100644
--- a/mesh.c
+++ b/mesh.c
@@ -192,9 +192,10 @@
 
 	/* Find out what mesh parameter we want to change. */
 	mdescr = NULL;
-	for (i = 0; ARRAY_SIZE(_mesh_param_descrs); i++)
+	for (i = 0; i < ARRAY_SIZE(_mesh_param_descrs); i++) {
 		if (!strcmp(_mesh_param_descrs[i].name, argv[0]))
 			return _mesh_param_descrs + i;
+	}
 
 	if (!mdescr) {
 		printf("Mesh_param must be one of: ");