mac80211: Exponential moving average estimate for rc80211_simple

This changes rc80211_simple failed frame percentage estimation to use an exponential moving average method. The old method used the plain tx success/failure counters. This made rate control very unresponsive after a short time of using the interface. Also tune the rc80211_simple parameters a little, so the tx rate is adapted a little more slowly.

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Ok, I played with the rate scaling a little more. This version of the patch calculates per_failed averages over time instead of just averaging as packets come in.

 net/mac80211/ieee80211_rate.h |    3 -
 net/mac80211/rc80211_simple.c |  107 +++++++++++++++++++++++++++++++++--------
 2 files changed, 86 insertions(+), 24 deletions(-)

index 2368813..9948d0f 100644
@@ -18,9 +18,6 @@
 #include "ieee80211_i.h"
 #include "sta_info.h"
 
-#define RATE_CONTROL_NUM_DOWN 20
-#define RATE_CONTROL_NUM_UP   15
-
 
 struct rate_control_extra {
 	/* values from rate_control_get_rate() to the caller: */

1.5.3.4