rt2x00: add new rt2800usb device Buffalo WLI-UC-G450

Add USB ID 0411:01fd for Buffalo WLI-UC-G450 wireless adapter,
RT chipset 3593

Signed-off-by: Anthony Wong <anthony.wong@ubuntu.com>
Cc: stable@vger.kernel.org
Acked-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>