driver_nl80211: implement shared AP channel op

Dump all AP interfaces using NL80211_CMD_GET_INTERFACE and make sure
the wiphy matches ours.

Signed-off-by: Arik Nemtsov <arik@wizery.com>
wpa_s: make SETBAND take immediate effect

Make SETBAND disconnect from the current AP if it's not
in the correct band. Also expire APs which aren't in the correct
band so scan results will immediately reflect the band change.

[Eyal - ammended commit description]

Signed-off-by: Panduranga Mallireddy <panduranga_mallireddy@ti.com>
Signed-off-by: Vishal Mahaveer <vishalm@ti.com>
Signed-off-by: Eyal Shapira <eyal@wizery.com>
Don't disable and select new network if SETBAND didn't change (ANDROID)

Current SETBAND would trigger network selection and as part of this
a scan attempt. This is not required in case SETBAND didn't change the
existing setting.

In Android which sends SETBAND immediately after WiFi startup this
would trigger needless scan attempts which would usually fail with -EBUSY
as another framework triggers scan was already going on.
The retry mechanism would then attempt further scans every 1 sec.

Signed-off-by: Eyal Shapira <eyal@wizery.com>
wpa_supplicant: fix scan with more than max_sched_scan_ssids

sched scan fills filter_ssids with non empty ssids
that may be non-hidden (not scan_ssid=1)
so we may get to a point where some hidden ssids aren't filtered
and we don't start a normal scan for them, since
total number of hidden ssid < max_sched_scan_ssids.
to solve this, we count all active ssids instead of just the
scan_ssid=1 ones