ARM: kirkwood: Add DTS file for NSA320

 Add a new DTS file to support the Zyxel NSA320 dual bay
 NAS Drive. This DTS just describes the features that
 work with the current kernel drivers. New drivers still
 need writing to support the temperature sensor, the
 power on behaviour control and the buzzer.

Signed-off-by: Adam Baker <linux@baker-net.org.uk>
Link: https://lkml.kernel.org/r/1396820569-3841-2-git-send-email-linux@baker-net.org.uk
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Acked-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>