ath9k: add struct ath_spec_scan_priv

and move rfs_chan_spec_scan to this struct. We will need it
for common spectral scan code.

Signed-off-by: Oleksij Rempel <linux@rempel-privat.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/spectral.h b/drivers/net/wireless/ath/ath9k/spectral.h
index 7b410c6..533d8a1 100644
--- a/drivers/net/wireless/ath/ath9k/spectral.h
+++ b/drivers/net/wireless/ath/ath9k/spectral.h
@@ -92,6 +92,9 @@
 	struct ath_radar_info radar_info;
 } __packed;
 
+struct ath_spec_scan_priv {
+	struct rchan *rfs_chan_spec_scan;
+};
 
 #define SPECTRAL_HT20_40_TOTAL_DATA_LEN	(sizeof(struct ath_ht20_40_fft_packet))