rt2x00: Fix RFKILL polling

The rfkill_poll callback function in the drivers check a bit
to see if the RFKILL key has been pressed. However when the
bit is set it means the radio is active and the device can be
used.

The wiphy_rfkill_set_hw_state() function expects the inversed,
so '1' must be send when the radio must be disabled.

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