wifi: nl80211: Add NAN Discovery Window (DW) notification

wifi: nl80211: Add NAN Discovery Window (DW) notification

This notification will be used by the device to inform user space
about upcoming DW. When received, user space will be able to prepare
multicast Service Discovery Frames (SDFs) to be transmitted during the
next DW using %NL80211_CMD_FRAME command on the NAN management interface.
The device/driver will take care to transmit the frames in the correct
timing. This allows to implement a synchronized Discovery Engine (DE)
in user space, if the device doesn't support DE offload.
Note that this notification can be sent before the actual DW starts as
long as the driver/device handles the actual timing of the SDF
transmission.

Signed-off-by: Andrei Otcheretianski <andrei.otcheretianski@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20250908140015.0e1d15031bab.I5b1721e61b63910452b3c5cdcdc1e94cb094d4c9@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>