rt2x00: Fix HW crypto key handling

When a crypto key is being removed, rt2x00mac should not
reset the key->hw_key_idx value because that will prevent
the driver from removing the correct key from the hardware.

Furthermore ffz() starts counting at 0 instead of 1, so we don't
need to substract 1 from the resulting value.

Signed-off-by: Stephen Blackheath <tramp.enshrine.stephen@blacksapphire.com>
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/rt2x00/rt2x00mac.c b/drivers/net/wireless/rt2x00/rt2x00mac.c
index 485c40d..2c6cc5c 100644
--- a/drivers/net/wireless/rt2x00/rt2x00mac.c
+++ b/drivers/net/wireless/rt2x00/rt2x00mac.c
@@ -543,7 +543,8 @@
 	 * provided but key 0 is not, then the key is not found
 	 * by the hardware during RX).
 	 */
-	key->hw_key_idx = 0;
+	if (cmd == SET_KEY)
+		key->hw_key_idx = 0;
 
 	if (key->flags & IEEE80211_KEY_FLAG_PAIRWISE)
 		set_key = rt2x00dev->ops->lib->config_pairwise_key;