arm: dts: imx6dl: Add pinctrl defines

Add imx6dl pinctrl defines support from Linux.

Here is the last commit:
"ARM: dts: imx: pinfunc: add MX6QDL_PAD_GPIO_6__ENET_IRQ"
(sha1: d8c765e0d1ddbd5032c2491c82cc9660c2f0e7f2)

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: Jagan Teki <jagan@amarulasolutions.com>