ARM: dts: kirkwood: Add DTS for Linksys EA4200v2/EA4500

This platform is based on a Marvell 88E6282 SoC and 88E6171 switch.

[gregory.clement@free-electrons.com: fix block comment style]
Signed-off-by: Bert Vermeulen <bert@biot.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Imre Kaloz <kaloz@openwrt.org>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>