Wireless: rt2x00: Add device id for Sweex LW323 to rt2800usb.c

This patch adds detection for the Sweex LW323 USB wireless network card
in the rt2x00 driver (just one line in rt2800usb.c).
It applies to linux-3.7-rc3.

Signed-off-by: Jaume Delclòs <jaume@delclos.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>