nl80211: Avoid AP mode BUG_ON hang with invalid lock assert

"cfg80211: add assert_cfg80211_lock() to ensure proper protection"
added assert_cfg80211_lock() calls into various places. At least
one of them, nl80211_send_wiphy(), should not have been there. That
triggers the BUG_ON in assert_cfg80211_lock() and pretty much kills
the kernel whenever someone runs hostapd.. Remove that call and make
assert_cfg80211_lock() use WARN_ON instead of BUG_ON to be a bit more
friendly to users.

Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/wireless/core.h b/net/wireless/core.h
index cd8e6e3..f6c53f5 100644
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -76,7 +76,7 @@
 
 static inline void assert_cfg80211_lock(void)
 {
-	BUG_ON(!mutex_is_locked(&cfg80211_mutex));
+	WARN_ON(!mutex_is_locked(&cfg80211_mutex));
 }
 
 /*
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 97f69be..531bb67 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -137,8 +137,6 @@
 	int i;
 	u16 ifmodes = dev->wiphy.interface_modes;
 
-	assert_cfg80211_lock();
-
 	hdr = nl80211hdr_put(msg, pid, seq, flags, NL80211_CMD_NEW_WIPHY);
 	if (!hdr)
 		return -1;