mac80211: add documentation and verbose variable names in

Add documentation and more verbose variable names to minstrel's
multi-rate-retry setup within function minstrel_get_rate() to
increase the readability of the algorithm.

Acked-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Thomas Huehn <thomas@net.t-labs.tu-berlin.de>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/rc80211_minstrel.h b/net/mac80211/rc80211_minstrel.h
index fda4a61..5fb5cb8 100644
--- a/net/mac80211/rc80211_minstrel.h
+++ b/net/mac80211/rc80211_minstrel.h
@@ -69,7 +69,7 @@
 	unsigned int sample_count;
 	int sample_deferred;
 
-	unsigned int sample_idx;
+	unsigned int sample_row;
 	unsigned int sample_column;
 
 	int n_rates;