wifi: cfg80211: add a flag for the first part of a scan

When there are no non-6 GHz channels, then the 6 GHz scan is the first
part of a split scan. Add a boolean denoting whether the scan is the
first part of a scan as it might be useful to drivers for internal
bookkeeping. This flag is also set if the scan is not split.

Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20250609213231.07e5a8a452ec.Ibf18f513e507422078fb31b28947e582a20df87a@changeid


Signed-off-by: Johannes Berg <johannes.berg@intel.com>