usb: phy: tegra: Cleanup error messages

Tegra's PHY driver has a mix of pr_err() and dev_err(), let's switch to
dev_err() and use common errors message formatting across the driver for
consistency.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>