ARM: dts: nitrogen6x: add CAN support

Regulator stuff copied from imx6qdl-tx6.dtsi, pin configuration
taken from Boundary Devices linux kernel tree ([1] and [2]).

[1] https://github.com/boundarydevices/linux-imx6/blob/boundary-imx_3.10.17_1.0.2_ga/arch/arm/boot/dts/imx6qdl-nitrogen6x.dtsi
[2] https://github.com/boundarydevices/linux-imx6/blob/boundary-imx_3.10.17_1.0.2_ga/arch/arm/boot/dts/imx6qdl.dtsi



Signed-off-by: Peter Seiderer <ps.report@gmx.net>
Tested-by: Eric Nelson <eric.nelson@boundarydevices.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>