ARM: dts: imx: ventana: remove unsupported dt nodes

The general device-tree rule is to not include nodes that do not have a driver
or bindings in a dts/dtsi. Remove the place-holder nodes from the Gateworks
Ventana boards until a time that a driver with proper bindings exists.

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Signed-off-by: Shawn Guo <shawn.guo@freescale.com>