cfg80211: add rfkill support

To be easier on drivers and users, have cfg80211 register an
rfkill structure that drivers can access. When soft-killed,
simply take down all interfaces; when hard-killed the driver
needs to notify us and we will take down the interfaces
after the fact. While rfkilled, interfaces cannot be set UP.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/wireless/Kconfig b/net/wireless/Kconfig
index 4500549..4428dd5 100644
--- a/net/wireless/Kconfig
+++ b/net/wireless/Kconfig
@@ -1,5 +1,6 @@
 config CFG80211
-        tristate "Improved wireless configuration API"
+	tristate "Improved wireless configuration API"
+	depends on RFKILL || !RFKILL
 
 config CFG80211_REG_DEBUG
 	bool "cfg80211 regulatory debugging"