rsi_find_sta
rsta = rsi_find_sta(common, wh->addr1);
struct rsi_sta *rsta = rsi_find_sta(common, wh->addr1);
rsta = rsi_find_sta(common, sta->addr);
rsta = rsi_find_sta(adapter->priv, sta->addr);
struct rsi_sta *rsi_find_sta(struct rsi_common *common, u8 *mac_addr);