usb: host: lpc32xx: don't unregister phy device

There is no need to unregister the I2C device, which serves as a phy
from host code, this should be done in the correspondent phy driver.

Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>