ath5k: dont use external sleep clock in AP mode

ath5k: dont use external sleep clock in AP mode

commit 5d6ce628f986d1a3c523cbb0a5a52095c48cc332 upstream.

When using the external sleep clock in AP mode, the
TSF increments too quickly, causing beacon interval
to be much lower than it is supposed to be, resulting
in lots of beacon-not-ready interrupts.

This fixes http://bugzilla.kernel.org/show_bug.cgi?id=14802.

Signed-off-by: Bob Copeland <me@bobcopeland.com>
Acked-by: Nick Kossifidis <mickflemm@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>