ath9k_hw: Use CONFIG_ATH9K_BTCOEX_SUPPORT

Make use of CONFIG_ATH9K_BTCOEX_SUPPORT in ath9k_hw
to provide a clean way of compilation without BTCOEX
support.

Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath9k/btcoex.h

@@ -105,7 +105,6 @@ void ath9k_hw_init_btcoex_hw(struct ath_hw *ah, int qnum);
 void ath9k_hw_btcoex_set_weight(struct ath_hw *ah,
 				u32 bt_weight,
 				u32 wlan_weight);
-void ath9k_hw_btcoex_enable(struct ath_hw *ah);
 void ath9k_hw_btcoex_disable(struct ath_hw *ah);
 void ath9k_hw_btcoex_bt_stomp(struct ath_hw *ah,
 			      enum ath_stomp_type stomp_type);