cfg80211: introduce scan IE limit attribute

This patch introduces a new attribute for a wiphy that tells
userspace how long the information elements added to a probe
request frame can be at most. It also updates the at76 to
advertise that it cannot support that, and, for now until I
can fix that, iwlwifi too.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/include/linux/nl80211.h b/include/linux/nl80211.h
index 27f230f..209cace 100644
--- a/include/linux/nl80211.h
+++ b/include/linux/nl80211.h
@@ -390,6 +390,8 @@
  *
  * @NL80211_ATTR_MAX_NUM_SCAN_SSIDS: number of SSIDs you can scan with
  *	a single scan request, a wiphy attribute.
+ * @NL80211_ATTR_MAX_SCAN_IE_LEN: maximum length of information elements
+ *	that can be added to a scan request
  *
  * @NL80211_ATTR_SCAN_FREQUENCIES: nested attribute with frequencies (in MHz)
  * @NL80211_ATTR_SCAN_SSIDS: nested attribute with SSIDs, leave out for passive
@@ -507,6 +509,8 @@
 
 	NL80211_ATTR_KEY_TYPE,
 
+	NL80211_ATTR_MAX_SCAN_IE_LEN,
+
 	/* add attributes here, update the policy in nl80211.c */
 
 	__NL80211_ATTR_AFTER_LAST,