ARM: Kirkwood: Make use of mvebu pincltl and gpio drivers

Select the generic mvebu kirkwood pincltr driver and generic mvebu
gpio driver. This requires minor changes to the DT, and the calls to
configure plat-orion gpio driver are removed.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Michael Walle <michael@walle.cc>
Tested-by: Simon Baatz <gmbnomis@gmail.com>
Tested-by: Jamie Lentin <jm@lentin.co.uk>
Tested-by: Joshua Coombs <josh.coombs@gmail.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>