We were setting RX_FILTER_BEACON even after entering STA mode,
which leads to a lot of unnecessary wakeups.  This should fix the
bug "Ath5k driver has too many interrupts per second at idle" at
http://bugzilla.kernel.org/show_bug.cgi?id=11749.
Signed-off-by: NBob Copeland <me@bobcopeland.com>
Acked-by: NNick Kossifidis <mickflemm@gmail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>