rt2x00: Move beacon and atim queue defines into rt2x00

As Johannes Berg indicated the BEACON and AFTER_BEACON
queue indeces in mac80211 should be removed because they
are too hardware specific. This patch adds the queue index
defines into rt2x00queue.h and removes the dependency of
the defines inside mac80211.h.

Also move rt2x00pci_beacon_update() into rt2400pci and
rt2500pci individually since it is no longer a generic
function since rt61 and rt2800 no longer use that.

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