mac80211: clean up beacon interval settings

We currently have two beacon interval configuration knobs:
hw.conf.beacon_int and vif.bss_info.beacon_int. This is
rather confusing, even though the former is used when we
beacon ourselves and the latter when we are associated to
an AP.

This just deprecates the hw.conf.beacon_int setting in favour
of always using vif.bss_info.beacon_int. Since it touches all
the beaconing IBSS code anyway, we can also add support for
the cfg80211 IBSS beacon interval configuration easily.

NOTE: The hw.conf.beacon_int setting is retained for now due
      to drivers still using it -- I couldn't untangle all
      drivers, some are updated in this patch.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/beacon.c b/drivers/net/wireless/ath/ath9k/beacon.c
index eb4759f..c17b838 100644
--- a/drivers/net/wireless/ath/ath9k/beacon.c
+++ b/drivers/net/wireless/ath/ath9k/beacon.c
@@ -320,8 +320,7 @@
 		u64 tsfadjust;
 		int intval;
 
-		intval = sc->hw->conf.beacon_int ?
-			sc->hw->conf.beacon_int : ATH_DEFAULT_BINTVAL;
+		intval = sc->beacon_interval ? : ATH_DEFAULT_BINTVAL;
 
 		/*
 		 * Calculate the TSF offset for this beacon slot, i.e., the
@@ -431,8 +430,7 @@
 	 * on the tsf to safeguard against missing an swba.
 	 */
 
-	intval = sc->hw->conf.beacon_int ?
-		sc->hw->conf.beacon_int : ATH_DEFAULT_BINTVAL;
+	intval = sc->beacon_interval ? : ATH_DEFAULT_BINTVAL;
 
 	tsf = ath9k_hw_gettsf64(ah);
 	tsftu = TSF_TO_TU(tsf>>32, tsf);
@@ -711,8 +709,7 @@
 	/* Setup the beacon configuration parameters */
 
 	memset(&conf, 0, sizeof(struct ath_beacon_config));
-	conf.beacon_interval = sc->hw->conf.beacon_int ?
-		sc->hw->conf.beacon_int : ATH_DEFAULT_BINTVAL;
+	conf.beacon_interval = sc->beacon_interval ? : ATH_DEFAULT_BINTVAL;
 	conf.listen_interval = 1;
 	conf.dtim_period = conf.beacon_interval;
 	conf.dtim_count = 1;