Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
diff --git a/net/mac80211/rc80211_minstrel_ht.c b/net/mac80211/rc80211_minstrel_ht.c
index 8212a8b..78e67d2 100644
--- a/net/mac80211/rc80211_minstrel_ht.c
+++ b/net/mac80211/rc80211_minstrel_ht.c
@@ -259,7 +259,7 @@
 		}
 	}
 
-	/* try to sample up to half of the availble rates during each interval */
+	/* try to sample up to half of the available rates during each interval */
 	mi->sample_count *= 4;
 
 	cur_prob = 0;