cfg80211: mark negative frequencies as invalid

Regulatory rules with negative frequencies are now
marked as invalid in is_valid_reg_rule().

Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/wireless/reg.c b/net/wireless/reg.c
index 4c7e39d..7a2ce27 100644
--- a/net/wireless/reg.c
+++ b/net/wireless/reg.c
@@ -330,7 +330,7 @@
 	const struct ieee80211_freq_range *freq_range = &rule->freq_range;
 	u32 freq_diff;
 
-	if (freq_range->start_freq_khz == 0 || freq_range->end_freq_khz == 0)
+	if (freq_range->start_freq_khz <= 0 || freq_range->end_freq_khz <= 0)
 		return false;
 
 	if (freq_range->start_freq_khz > freq_range->end_freq_khz)