mac80211: check DSSS params IE length in parser

It's always just one byte, so check for that and
remove the length field from the parser struct.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index e12fedc..f76c58f 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -2695,7 +2695,7 @@
 		}
 	}
 
-	if (elems->ds_params && elems->ds_params_len == 1)
+	if (elems->ds_params)
 		freq = ieee80211_channel_to_frequency(elems->ds_params[0],
 						      rx_status->band);
 	else