Currently usb_put_transceiver calls put_device so this is a no-op but it
is better to keep API usage consistent as ehci->transceiver is allocated
with usb_get_transceiver.

While at there remove one extra ehci->transceiver test as the code block
has already tested it.
Signed-off-by: Jarkko Nikula <jarkko.nikula@bitmer.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>