cfg80211: default to regulatory max power for channel

If the driver does not specify a maximum power output, default to the
regulatory max.

Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/wireless/reg.c b/net/wireless/reg.c
index 8cc6037..185488d 100644
--- a/net/wireless/reg.c
+++ b/net/wireless/reg.c
@@ -136,7 +136,10 @@
 	chan->flags = flags;
 	chan->max_antenna_gain = min(chan->orig_mag,
 					 rg->max_antenna_gain);
-	chan->max_power = min(chan->orig_mpwr, rg->max_power);
+	if (chan->orig_mpwr)
+		chan->max_power = min(chan->orig_mpwr, rg->max_power);
+	else
+		chan->max_power = rg->max_power;
 }
 
 static void handle_band(struct ieee80211_supported_band *sband,