ARM: dts: colibri-imx6: move vbus-supply to module level device tree

Move USB VBUS supply from single carrier board to module level device
tree. This pin is as per Colibri module family standard.

Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>