Don't check if the radio is enabled in rt2x00lib_toggle_rx,
this is required since the link tuner should be disabled
when shutting down the device. The remaining calls inside the
rt2x00lib_toggle_rx handler should deliver no problems when
called while the radio is done.

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