mac80211: initialize the last rx time when creating a station

should hopefully finally take care of the nasty reassociation issues which showed up as
Jan  1 00:51:10 OpenWrt daemon.info hostapd: wlan0: STA 00:xx:xx:xx:xx:xx IEEE 802.11: deauthenticated due to inactivity
right after associating, leading to an immediate disconnect.
Will probably fix #8343, #8830 and others.

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@26251 3c298f89-4303-0410-b956-a3cf2f4a3e73

package/mac80211/patches/570-mac80211_initialize_last_rx.patch

+--- a/net/mac80211/sta_info.c
++++ b/net/mac80211/sta_info.c
+@@ -243,6 +243,7 @@ struct sta_info *sta_info_alloc(struct i
+ 	memcpy(sta->sta.addr, addr, ETH_ALEN);
+ 	sta->local = local;
+ 	sta->sdata = sdata;
++	sta->last_rx = jiffies;
+ 
+ 	ewma_init(&sta->avg_signal, 1024, 8);
+