Drivers should be allowed to simply get a complete new beacon when
set_tim() is invoked (and set_tim() is required for drivers that
just want a beacon template!), so we need to update our own TIM
bitmap before calling set_tim() so that getting the beacon will
now get an already updated beacon.
Signed-off-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>