ath9k: Fill remove_sta_debugfs() callback

Remove the rate control statistics debugfs file properly
via remove_sta_debugfs(). Also, check for both MAC80211_DEBUGFS
and ATH9K_DEBUGFS config options.

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

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

@@ -211,7 +211,9 @@ struct ath_rate_priv {
 	struct ath_rateset neg_ht_rates;
 	const struct ath_rate_table *rate_table;
 
+#if defined(CONFIG_MAC80211_DEBUGFS) && defined(CONFIG_ATH9K_DEBUGFS)
 	struct dentry *debugfs_rcstats;
+#endif
 	struct ath_rc_stats rcstats[RATE_TABLE_SIZE];
 };