mac80211_hwsim: fix bogus warning

A typo slipped into my patch to configure beacon intervals
properly -- this warning is supposed to trigger when the
beacon interval is zero, not non-zero.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/mac80211_hwsim.c

@@ -618,7 +618,7 @@ static void mac80211_hwsim_bss_info_changed(struct ieee80211_hw *hw,
 		printk(KERN_DEBUG "  %s: BCNINT: %d\n",
 		       wiphy_name(hw->wiphy), info->beacon_int);
 		data->beacon_int = 1024 * info->beacon_int / 1000 * HZ / 1000;
-		if (WARN_ON(data->beacon_int))
+		if (WARN_ON(!data->beacon_int))
 			data->beacon_int = 1;
 	}