wifi: cfg80211: Fix an error handling path in cfg80211_wext_siwscan()

wifi: cfg80211: Fix an error handling path in cfg80211_wext_siwscan()

If the test against IEEE80211_MAX_SSID_LEN fails, then 'creq' leaks.
Use the existing error handling path to fix it.

Fixes: 2a5193119269 ("cfg80211/nl80211: scanning (and mac80211 update to use it)")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://patch.msgid.link/a1be7eea4da0da18f90589af252bb76a18a61978.1781984889.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Johannes Berg <johannes.berg@intel.com>