ARM: dts: armada-385-linksys: flatten dependants

Flatten dts of individual boards to match the new style used in
armada-385-linksys.dtsi and for the Rango addition.

* Caiman - Linksys WRT1200AC v1 & v2
* Cobra - Linksys WRT1900AC v2
* Shelby - Linksys WRT1900ACS v1 & v2

Signed-off-by: Ralph Sennhauser <ralph.sennhauser@gmail.com>
Signed-off-by: Imre Kaloz <kaloz@openwrt.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>