rt2800lib incorrectly detected whether RT2800USB was enabled because
it didn't account for a modularized RT2800USB driver.
Signed-off-by: NGertjan van Wingerde <gwingerde@gmail.com>
Acked-by: NIvo van Doorn <IvDoorn@gmail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>