mac80211: restructure per-rate throughput calculation into function

This patch moves Minstrels and Minstrel-HTs per-rate throughput
calculation (EWMA(thr)) into a dedicated function to be called.
Therefore the variable "unsigned int cur_tp" within struct
"minstrel_rate_stats" becomes obsolete.  and is removed to free
up its space.

Signed-off-by: Thomas Huehn <thomas@net.t-labs.tu-berlin.de>
Acked-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --cc net/mac80211/rc80211_minstrel.c
Simple merge

diff --cc net/mac80211/rc80211_minstrel.h
Simple merge

diff --cc net/mac80211/rc80211_minstrel_debugfs.c
Simple merge

diff --cc net/mac80211/rc80211_minstrel_ht.c
Simple merge

diff --cc net/mac80211/rc80211_minstrel_ht.h
Simple merge

diff --cc net/mac80211/rc80211_minstrel_ht_debugfs.c
Simple merge