rockchip: dts: rk3399-puma: release reset of on-module USB3 hub via vbus-gpio

On the RK3399-Q7, the on-module USB3 hub is held in reset at boot-up
to save power and needs to be woken up using GPIO4A3.

Note that this is not a negated reset-signal (due to a level shifter
being needed for this signal anyway), but a negated enable-signal:
to enable, we need to output LOW (i.e. 0)... so we mark this as an
ACTIVE_LOW signal.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>