arm: dts: Add devicetree for i.MX6DQL

Add i.MX6DQL dtsi support from Linux.

Here is the last commit:
"ARM: dts: imx6qdl: Fix SPDIF regression"
(sha1: f065e9e4addd75c21bb976bb2558648bf4f61de6)

Cc: Peng Fan <peng.fan@nxp.com>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Cc: Matteo Lisi <matteo.lisi@engicam.com>
Cc: Michael Trimarchi <michael@amarulasolutions.com>
Signed-off-by: NJagan Teki <jagan@amarulasolutions.com>