ARM: mvebu: Add Netgear ReadyNAS 102 board

All hardware parts of the (Armada 370 based) NETGEAR ReadyNAS 102 are
supported by mainline kernel (USB 3.0 rear ports, USB 2.0 front port,
Gigabit controller and PHY, serial port, leds, buttons, SATA ports,
G762 fan controller) except for:

 - the Intersil ISL12057 I2C RTC Chip,
 - the Armada NAND controller.

Support for both of those is currently work in progress and does not
prevent boot.

Signed-off-by: Arnaud Ebalard <arno@natisbad.org>
Acked-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>