ARM: dts: socfpga: add gpio pieces

The cycloneV has three gpio controllers, each one with 29 gpios. This patch
adds the three controller with the gpio driver which is now sitting the
gpio tree.

Cc: devicetree@vger.kernel.org
Acked-by: Alan Tull <atull@altera.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Dinh Nguyen <dinguyen@altera.com>