ARM: dts: kirkwood: ReadyNAS NV+v2: Add LCD panel

The NV+ v2 has a WH1602 LCD panel (which is just a rebranded HD44780),
similar to the Netgear RN104, just with different GPIO assignments.

Signed-off-by: Brian J. Tarricone <brian@tarricone.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>