ath6kl: fix compilation when NL80211_TESTMODE is disabled

ERROR: "ath6kl_tm_rx_report_event"
[drivers/net/wireless/ath/ath6kl/ath6kl.ko] undefined

Reported-by: Jouni Malinen <jouni@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>

drivers/net/wireless/ath/ath6kl/testmode.h

@@ -16,5 +16,21 @@
 
 #include "core.h"
 
+#ifdef CONFIG_NL80211_TESTMODE
+
 void ath6kl_tm_rx_report_event(struct ath6kl *ar, void *buf, size_t buf_len);
 int ath6kl_tm_cmd(struct wiphy *wiphy, void *data, int len);
+
+#else
+
+static inline void ath6kl_tm_rx_report_event(struct ath6kl *ar, void *buf,
+					     size_t buf_len)
+{
+}
+
+static inline int ath6kl_tm_cmd(struct wiphy *wiphy, void *data, int len)
+{
+	return 0;
+}
+
+#endif