mac80211: support scan features for improved scan privacy

Support the new random SN and minimal probe request contents
scan flags for the case of software scan - for hardware scan
the drivers need to opt in, but may need to do only that,
depending on their implementation.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 0325133..b744b10 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -1433,6 +1433,9 @@
 				chandef->chan->center_freq);
 	}
 
+	if (flags & IEEE80211_PROBE_FLAG_MIN_CONTENT)
+		goto done;
+
 	/* insert custom IEs that go before HT */
 	if (ie && ie_len) {
 		static const u8 before_ht[] = {
@@ -1510,6 +1513,7 @@
 	return pos - buffer;
  out_err:
 	WARN_ONCE(1, "not enough space for preq IEs\n");
+ done:
 	return pos - buffer;
 }