carl9170: improve site survey

The firmware keeps track of channel usage. This data can
be used by the automatic channel selection to find the
*best* channel.

Survey data from wlan22
	frequency:                      2412 MHz [in use]
	noise:                          -86 dBm
	channel active time:            3339608 ms
	channel busy time:              270982 ms
	channel transmit time:          121515 ms
Survey data from wlan22
	frequency:                      2417 MHz
	noise:                          -86 dBm
	channel active time:            70 ms
	channel busy time:              2 ms
	channel transmit time:          1 ms

Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/carl9170/cmd.h b/drivers/net/wireless/ath/carl9170/cmd.h
index d5f95bd..885c427 100644
--- a/drivers/net/wireless/ath/carl9170/cmd.h
+++ b/drivers/net/wireless/ath/carl9170/cmd.h
@@ -50,6 +50,7 @@
 int carl9170_reboot(struct ar9170 *ar);
 int carl9170_mac_reset(struct ar9170 *ar);
 int carl9170_powersave(struct ar9170 *ar, const bool power_on);
+int carl9170_collect_tally(struct ar9170 *ar);
 int carl9170_bcn_ctrl(struct ar9170 *ar, const unsigned int vif_id,
 		       const u32 mode, const u32 addr, const u32 len);