rt2x00: Don't check whether hardware crypto is enabled when reading RXD.

We should simply follow what the hardware told us it has done.

Signed-off-by: Gertjan van Wingerde <gwingerde@gmail.com>
Acked-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>