mac80211: Fix the maximum transmit power with power constraint

The local maximum transmit power for a channel is defined as the maximum
regulatory transmission power minus the local power constraint specified
for the channel in the Power Constraint element. (7.3.2.15 IEEE80211 2007)

Signed-off-by: Hong Wu <hong.wu@dspg.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index ecb4c84..95d3964 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -547,7 +547,7 @@
 	if (pwr_constr_elem_len != 1)
 		return;
 
-	if ((*pwr_constr_elem <= conf->channel->max_power) &&
+	if ((*pwr_constr_elem <= conf->channel->max_reg_power) &&
 	    (*pwr_constr_elem != sdata->local->power_constr_level)) {
 		sdata->local->power_constr_level = *pwr_constr_elem;
 		ieee80211_hw_config(sdata->local, 0);