Linux keeps scan results up to 15 seconds. This can be a problem for fast
moving clients: they get back stale data. But if the kernel reports the age
of the BSS items, then user-space can simply weed out old entries by itself.
Signed-off-by: Holger Schurig <hs4233@mail.mn-solutions.de> Acked-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>