ARM: dts: colibri-imx6ull: update device tree

Fix compatible node to use regular Toradex notation.
Annotate device tree with standard Colibri pin muxing comments.
Use open-drain I2C pin muxings.
Alphabetically re-order iomuxc nodes.
Rename snvs-ad7879-int-grp touch interrupt node as per Linux device tree.

Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Reviewed-by: Igor Opaniuk <igor.opaniuk@toradex.com>