exynos: dts: Correct USB vbus-gpio numbering for Snow

The current vbus GPIOs on snow make very little sense, their number is
far above the maximum. As a result, USB doesn't work on snow.

Correct the GPIO numbering so they match the current scheme for exynos5.
Tested both EHCI and XHCI to correctly work after this change.

Signed-off-by: Sjoerd Simons <sjoerd.simons@collabora.co.uk>
Acked-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>