Fix feather diy (#1892)

* Fix variant

* Fix feather diy target

variants/feather_diy/variant.cpp

@@ -0,0 +1,24 @@
+/*
+  Copyright (c) 2014-2015 Arduino LLC.  All right reserved.
+  Copyright (c) 2016 Sandeep Mistry All right reserved.
+  Copyright (c) 2018, Adafruit Industries (adafruit.com)
+
+  This library is free software; you can redistribute it and/or
+  modify it under the terms of the GNU Lesser General Public
+  License as published by the Free Software Foundation; either
+  version 2.1 of the License, or (at your option) any later version.
+
+  This library is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+  See the GNU Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public
+  License along with this library; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+
+#include "variant.h"
+#include "nrf.h"
+#include "wiring_constants.h"
+#include "wiring_digital.h"