Modify Tegra30 default USB2 phy_type to UTMI; this matches
power-on-reset defaults and is expected to be the common case.

The current implementation is likely an incorrect
carry-over from Tegra20, where USB2 does default to ULPI.
Signed-off-by: Eric Brower <ebrower@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>