ARM: tegra: Combine VBUS enable pins into one node

Both USB_VBUS_EN0 and USB_VBUS_EN1 are configured the same way, so they
can be combined into a single node. While at it, don't configure them as
pull-up since they already have external pull-ups. Also U-Boot doesn't
configure them as pull-up either.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>