Add QCA vendor command to support beacon reporting feature

Add QCA vendor command to support beacon reporting feature

Add a QCA vendor sub command QCA_NL80211_VENDOR_SUBCMD_BEACON_REPORTING
to implement beacon reporting feature. Different operations required to
implement this feature can be specified in
QCA_WLAN_VENDOR_ATTR_BEACON_REPORTING_OP_TYPE.

Userspace requests the driver/firmware to periodically report received
Beacon frames whose BSSID matches the current connected BSS's MAC
address. If userspace requests the driver/firmware to send beacon
reports actively, the driver encapsulates the details of the beacon in
an event and sends it to userspace asynchronously. Otherwise, the driver
will only update the beacon in cfg80211 scan cache but will not send any
event to userspace.

If this command is not issued, the current behavior of the
driver/firmware is to update the cfg80211 scan cache only when there is
a scan issued by the host in progress or whenever there is a change in
IEs of the Beacon frames from the current connected BSS.

The userspace requests the driver/firmware to stop reporting beacons
when reporting is not required anymore. If the driver/firmware is not
able to receive Beacon frames because of other Wi-Fi operations such as
off-channel activities, etc., the driver/firmware sends a pause event to
userspace and stops reporting Beacon frames. The driver/firmware
indicates whether the beacon reporting automatically resumes later by
using the QCA_WLAN_VENDOR_ATTR_BEACON_REPORTING_AUTO_RESUMES flag. If
userspace doesn't want the beacon reporting to be resumed automatically,
userspace can send QCA_WLAN_VENDOR_BEACON_REPORTING_OP_STOP command to
the driver to stop beacon reporting.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>