mt76: mt7615: add missing declaration in mt7615.h

Add mt7615_mcu_wait_response declaration in mt7615.h since it will be
reused adding usb support to mt7615 driver

Reported-by: kbuild test robot <lkp@intel.com>
Fixes: 044a432 ("mt76: mt7615: introduce mt7615_mcu_wait_response")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/d341335a636b6ccd088dd2cfeec2d296eb4dc8c7.1584534454.git.lorenzo@kernel.org

drivers/net/wireless/mediatek/mt76/mt7615/mt7615.h

@@ -383,6 +383,7 @@ int mt7615_mac_wtbl_set_key(struct mt7615_dev *dev, struct mt76_wcid *wcid,
 			    enum set_key_cmd cmd);
 void mt7615_mac_reset_work(struct work_struct *work);
 
+int mt7615_mcu_wait_response(struct mt7615_dev *dev, int cmd, int seq);
 int mt7615_mcu_set_dbdc(struct mt7615_dev *dev);
 int mt7615_mcu_set_eeprom(struct mt7615_dev *dev);
 int mt7615_mcu_set_mac_enable(struct mt7615_dev *dev, int band, bool enable);