mac80211: convert HW flags to unsigned long bitmap

As we're running out of hardware capability flags pretty quickly,
convert them to use the regular test_bit() style unsigned long
bitmaps.

This introduces a number of helper functions/macros to set and to
test the bits, along with new debugfs code.

The occurrences of an explicit __clear_bit() are intentional, the
drivers were never supposed to change their supported bits on the
fly. We should investigate changing this to be a per-frame flag.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/rsi/rsi_91x_mac80211.c

@@ -1062,10 +1062,9 @@ int rsi_mac80211_attach(struct rsi_common *common)
 	hw->priv = adapter;
 	adapter->hw = hw;
 
-	hw->flags = IEEE80211_HW_SIGNAL_DBM |
-		    IEEE80211_HW_HAS_RATE_CONTROL |
-		    IEEE80211_HW_AMPDU_AGGREGATION |
-		    0;
+	ieee80211_hw_set(hw, SIGNAL_DBM);
+	ieee80211_hw_set(hw, HAS_RATE_CONTROL);
+	ieee80211_hw_set(hw, AMPDU_AGGREGATION);
 
 	hw->queues = MAX_HW_QUEUES;
 	hw->extra_tx_headroom = RSI_NEEDED_HEADROOM;