carl9170: reduce channel change delay

By removing two "safety" msleeps (and an echo nop), the
channel change delay is effectively halved. Previously,
the delay could be as long as 260 ms and the device
could not go off-channel without risking to miss the
next DTIM beacon [interval ~307 ms].
Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/carl9170/phy.c

@@ -1029,8 +1029,6 @@ static int carl9170_init_rf_bank4_pwr(struct ar9170 *ar, bool band5ghz,
 	if (err)
 		return err;
 
-	msleep(20);
-
 	return 0;
 }
 
@@ -1660,12 +1658,6 @@ int carl9170_set_channel(struct ar9170 *ar, struct ieee80211_channel *channel,
 			return err;
 
 		cmd = CARL9170_CMD_RF_INIT;
-
-		msleep(100);
-
-		err = carl9170_echo_test(ar, 0xaabbccdd);
-		if (err)
-			return err;
 	} else {
 		cmd = CARL9170_CMD_FREQUENCY;
 	}