ARM: tegra: Whistler: remove unused USB alias

ARM: tegra: Whistler: remove unused USB alias

Port USB1 on Whistler is intended as a device port for USB recovery.
Whistler's DT currently contains an alias for this USB port, even though
Whistler's config doesn't enable multiple USB controllers, so the alias
is unused. Remove the unused alias for consistency for now. Similar,
explicitly disable the port in the device tree too.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>