ARM: dts: sunxi: enable otg port on the sun7i-a20-olinuxino-lime2

This patch enables the musb-otg USB controller on the Lime2. The Lime2
differs from the Lime1 series in pins used for usb0 power.

Tested on a OlinuXino Lime2-4GB.

Signed-off-by: Olliver Schinagl <oliver@schinagl.nl>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>