mac80211: support hardware TX fragmentation offload

The lower driver is notified when the fragmentation threshold changes
and upon a reconfig of the interface.

If the driver supports hardware TX fragmentation, don't fragment
packets in the stack.

Signed-off-by: Arik Nemtsov <arik@wizery.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/driver-trace.h b/net/mac80211/driver-trace.h
index 6831fb1..431d655 100644
--- a/net/mac80211/driver-trace.h
+++ b/net/mac80211/driver-trace.h
@@ -531,6 +531,27 @@
 	)
 );
 
+TRACE_EVENT(drv_set_frag_threshold,
+	TP_PROTO(struct ieee80211_local *local, u32 value),
+
+	TP_ARGS(local, value),
+
+	TP_STRUCT__entry(
+		LOCAL_ENTRY
+		__field(u32, value)
+	),
+
+	TP_fast_assign(
+		LOCAL_ASSIGN;
+		__entry->value = value;
+	),
+
+	TP_printk(
+		LOCAL_PR_FMT " value:%d",
+		LOCAL_PR_ARG, __entry->value
+	)
+);
+
 TRACE_EVENT(drv_set_rts_threshold,
 	TP_PROTO(struct ieee80211_local *local, u32 value),