cfg80211: clean up signal type

It wasn't a good idea to make the signal type a per-BSS option,
although then it is closer to the actual value. Move it to be
a per-wiphy setting, update mac80211 to match.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index fce9d08..f38db4d 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -861,6 +861,11 @@
 	/* mac80211 always supports monitor */
 	local->hw.wiphy->interface_modes |= BIT(NL80211_IFTYPE_MONITOR);
 
+	if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
+		local->hw.wiphy->signal_type = CFG80211_SIGNAL_TYPE_MBM;
+	else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
+		local->hw.wiphy->signal_type = CFG80211_SIGNAL_TYPE_UNSPEC;
+
 	result = wiphy_register(local->hw.wiphy);
 	if (result < 0)
 		goto fail_wiphy_register;