cfg80211: force WIPHY_FLAG_CUSTOM_REGULATORY on wiphy_apply_custom_regulatory()

wiphy_apply_custom_regulatory() implies WIPHY_FLAG_CUSTOM_REGULATORY
but we never enforced it, do that now and warn if the driver
didn't set it. All drivers should be following this today already.

Having WIPHY_FLAG_CUSTOM_REGULATORY does not however mean you will
use wiphy_apply_custom_regulatory() though, you may have your own
_orig value set up tools / helpers. The intel drivers are examples
of this type of driver.

Signed-off-by: Luis R. Rodriguez <mcgrof@do-not-panic.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index c1b8874..b7a825e 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -2441,7 +2441,9 @@
  * 	has its own custom regulatory domain and cannot identify the
  * 	ISO / IEC 3166 alpha2 it belongs to. When this is enabled
  * 	we will disregard the first regulatory hint (when the
- * 	initiator is %REGDOM_SET_BY_CORE).
+ * 	initiator is %REGDOM_SET_BY_CORE). Drivers that use
+ * 	wiphy_apply_custom_regulatory() should have this flag set
+ * 	or the regulatory core will set it for wiphy.
  * @WIPHY_FLAG_STRICT_REGULATORY: tells us the driver for this device will
  *	ignore regulatory domain settings until it gets its own regulatory
  *	domain via its regulatory_hint() unless the regulatory hint is
@@ -3471,6 +3473,9 @@
  * custom regulatory domain will be trusted completely and as such previous
  * default channel settings will be disregarded. If no rule is found for a
  * channel on the regulatory domain the channel will be disabled.
+ * Drivers using this for a wiphy should also set the wiphy flag
+ * WIPHY_FLAG_CUSTOM_REGULATORY or cfg80211 will set it for the wiphy
+ * that called this helper.
  */
 void wiphy_apply_custom_regulatory(struct wiphy *wiphy,
 				   const struct ieee80211_regdomain *regd);