VHT: Fix memory leak in STA entry

Commit de3cdf354a30256ece16866ff5a283b66e1471ae adding copying of the
STA's VHT capabilities into the STA entry on the AP. This was done in
allocated memory, but that new memory allocation was not freed anywhere.

Signed-hostap: Jouni Malinen <jouni@qca.qualcomm.com>

src/ap/sta_info.c

@@ -262,6 +262,7 @@ void ap_free_sta(struct hostapd_data *hapd, struct sta_info *sta)
 	wpabuf_free(sta->hs20_ie);
 
 	os_free(sta->ht_capabilities);
+	os_free(sta->vht_capabilities);
 	hostapd_free_psk_list(sta->psk);
 	os_free(sta->identity);
 	os_free(sta->radius_cui);