ARM: dts: imx7-colibri: Add touch controllers

Add touch controller that is connected over an I2C bus.
It is disabled by default because the pins are also used for PWM,
which is the standard use for colibri boards.

Signed-off-by: Philippe Schenker <philippe.schenker@toradex.com>
Acked-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Reviewed-by: Oleksandr Suvorov <oleksandr.suvorov@toradex.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>