mac80211: clean up global debugfs statistics

The debugfs statistics macros are pointlessly verbose, so change
that macro to just have a single argument. While at it, remove
the unused counters and rename rx_expand_skb_head2 to the better
rx_expand_skb_head_defrag.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index e9f36f7..987ec23 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1282,7 +1282,6 @@
 	/* TX/RX handler statistics */
 	unsigned int tx_handlers_drop;
 	unsigned int tx_handlers_queued;
-	unsigned int tx_handlers_drop_fragment;
 	unsigned int tx_handlers_drop_wep;
 	unsigned int tx_handlers_drop_not_assoc;
 	unsigned int tx_handlers_drop_unauth_port;
@@ -1293,8 +1292,7 @@
 	unsigned int rx_handlers_drop_short;
 	unsigned int tx_expand_skb_head;
 	unsigned int tx_expand_skb_head_cloned;
-	unsigned int rx_expand_skb_head;
-	unsigned int rx_expand_skb_head2;
+	unsigned int rx_expand_skb_head_defrag;
 	unsigned int rx_handlers_fragments;
 	unsigned int tx_status_drop;
 #define I802_DEBUG_INC(c) (c)++