Scheduled scan implementation in cfg80211/mac80211!

The scheduled scan implementation has just been applied in the wireless-next tree, so it will probably be included in 2.6.40!

This is a very cool feature that the WL12XX hardware supports, which allows us to save power when scanning for APs to become available.  The hardware and firmware can perform scans periodically on their own, so the host processor doesn't have to wake up.  When an AP, it wakes up the host for processing.

In this initial implementation, we don't support filtering, but in the near future we will implement it as well.  With filtering, this feature becomes even more interesting, because we can tell the firmware which SSIDs we're interested in, so the host will not wake up until there is a relevant SSID available.  But this is a story for a future post. :)