Add a madwifi patch by Brian Candler, which fixes minstrel when operating without multi-rate retry.

Should lead to significant performance improvements when dealing with stations in B/G mixed mode.
Fixes #2876


git-svn-id: svn://svn.openwrt.org/openwrt/trunk@9820 3c298f89-4303-0410-b956-a3cf2f4a3e73

package/madwifi/patches/110-minstrel_counters.patch

@@ -0,0 +1,22 @@
+diff --exclude '*~' -uNr madwifi-dfs-r3053.orig/ath_rate/minstrel/minstrel.c madwifi-dfs-r3053/ath_rate/minstrel/minstrel.c
+--- madwifi-dfs-r3053.orig/ath_rate/minstrel/minstrel.c	2007-12-21 13:34:23.000000000 +0000
++++ madwifi-dfs-r3053/ath_rate/minstrel/minstrel.c	2007-12-21 14:29:07.000000000 +0000
+@@ -449,7 +449,6 @@
+ 		const struct ath_desc *ds = &bf->bf_desc[0];
+ 		int final_rate = 0;
+ 		int tries = 0;
+-		int ndx = -1;
+ 		int mrr;
+ 		int final_ndx;
+ 		int rate0, tries0, ndx0;
+@@ -488,8 +487,8 @@
+ 		mrr = sc->sc_mrretry && !(ic->ic_flags & IEEE80211_F_USEPROT) && ENABLE_MRR;
+ 
+ 		if (!mrr) {
+-			if ((0 <= ndx) && (ndx < sn->num_rates)) {
+-				sn->rs_rateattempts[ndx]++; /* only one rate was used */
++			if ((0 <= final_ndx) && (final_ndx < sn->num_rates)) {
++				sn->rs_rateattempts[final_ndx]++; /* only one rate was used */
+ 			}
+ 			return;
+ 		}