cfg80211: allow drivers that agree on regulatory to agree

This allows drivers that agree on regulatory to share their
regulatory domain.

Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/wireless/reg.c

@@ -1157,6 +1157,16 @@ static int ignore_request(struct wiphy *wiphy, enum reg_set_by set_by,
 				return 0;
 			return -EALREADY;
 		}
+
+		/*
+		 * This would happen if you unplug and plug your card
+		 * back in or if you add a new device for which the previously
+		 * loaded card also agrees on the regulatory domain.
+		 */
+		if (last_request->initiator == REGDOM_SET_BY_DRIVER &&
+		    alpha2_equal(cfg80211_regdomain->alpha2, alpha2))
+			return -EALREADY;
+
 		return REG_INTERSECT;
 	case REGDOM_SET_BY_USER:
 		if (last_request->initiator == REGDOM_SET_BY_COUNTRY_IE)