ARM: dts: sun9i: Enable USB support on A80 Optimus board

On the Optimus board, all three USB hosts can be used.
HCI0 and HCI2 are available through the USB connector.
HCI1 is available with HSIC through 2 pins on the GPIO
expansion header.

This patch also adds a regulator for HCI2/USB3's VBUS.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>