ARM: dts: imx6qdl-vicut1: Factor out common parts of 12inch board variants

Factor out common parts of vicut1 and vicutp to reduce maintenance
overhead.

Signed-off-by: David Jander <david@protonic.nl>
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>