mac80211: don't return -EINVAL upon iwconfig wlan0 rts auto

This patch avoids returning -EINVAL upon iwconfig wlan0 rts auto. If
rts->fixed is 0, then we should choose a default value instead of failing.
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/mac80211/wext.c

@@ -721,6 +721,9 @@ static int ieee80211_ioctl_siwrts(struct net_device *dev,
 
 	if (rts->disabled)
 		local->rts_threshold = IEEE80211_MAX_RTS_THRESHOLD;
+	else if (!rts->fixed)
+		/* if the rts value is not fixed, then take default */
+		local->rts_threshold = IEEE80211_MAX_RTS_THRESHOLD;
 	else if (rts->value < 0 || rts->value > IEEE80211_MAX_RTS_THRESHOLD)
 		return -EINVAL;
 	else