tools/gpio: create GPIO tools

This creates GPIO tools under tools/gpio/* and adds a single
example program to list the GPIOs on a system. When proper
devices are created it provides this minimal output:

Cc: Johan Hovold <johan@kernel.org>
Cc: Michael Welling <mwelling@ieee.org>
Cc: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/tools/gpio/gpio-utils.c b/tools/gpio/gpio-utils.c
new file mode 100644
index 0000000..8208718
--- /dev/null
+++ b/tools/gpio/gpio-utils.c
@@ -0,0 +1,11 @@
+/*
+ * GPIO tools - helpers library for the GPIO tools
+ *
+ * Copyright (C) 2015 Linus Walleij
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+#include "gpio-utils.h"