ARM: dts: imx6dl-colibri: Drop dedicated v1.1 device tree

Drop Colibri V1.1 device tree, this is just a duplicate of Colibri V1.0
with the possibility to use SD cards in UHS mode if the carrier board
does not have 3.3V pull up resistor.

The dedicated device tree kept the feature switched of by setting
the no-1-8-v property and thus does not offer anything different
than what the regular device tree does.

Thus drop the dedicated device tree and merge the preparation to
allow enabling the feature should a carrier without pull ups
be used into the regular device tree.

Signed-off-by: Max Krummenacher <max.krummenacher@toradex.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>