ath10k: remove unused prototype

The function does not exist and thus, the prototype can be removed.
Signed-off-by: Erik Stromdahl <erik.stromdahl@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/ath/ath10k/htt.h

@@ -1933,7 +1933,6 @@ void ath10k_htt_htc_t2h_msg_handler(struct ath10k *ar, struct sk_buff *skb);
 bool ath10k_htt_t2h_msg_handler(struct ath10k *ar, struct sk_buff *skb);
 int ath10k_htt_h2t_ver_req_msg(struct ath10k_htt *htt);
 int ath10k_htt_h2t_stats_req(struct ath10k_htt *htt, u8 mask, u64 cookie);
-int ath10k_htt_send_rx_ring_cfg_ll(struct ath10k_htt *htt);
 int ath10k_htt_h2t_aggr_cfg_msg(struct ath10k_htt *htt,
 				u8 max_subfrms_ampdu,
 				u8 max_subfrms_amsdu);