ath9k: Remove dead code in recv.c

The structure struct ieee80211_rx_status *rxs is no longer needed to be
passed to ath_rx_send_to_mac80211 function

Signed-off-by: Mohammed Shafi Shajakhan <mshajakhan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>