ARM: dts: imx6: add support for Ka-Ro TX6 modules

This patch adds support for the Ka-Ro electronics GmbH TX6 modules.
There are five distinct module types with either i.MX6Q or i.MX6DL and
LVDS or LCD display interface and one DTS file for a complete system
with an i.MX6DL based TX6 module and a baseboard mounted on the back
of a display (imx6dl-tx6dl-comtft.dts).

Signed-off-by: Lothar Waßmann <LW@KARO-electronics.de>
Signed-off-by: Shawn Guo <shawn.guo@freescale.com>