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: NStephen Blackheath <tramp.enshrine.stephen@blacksapphire.com>
Signed-off-by: NIvo van Doorn <IvDoorn@gmail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rt2x00/rt2x00mac.c

@@ -543,7 +543,8 @@ int rt2x00mac_set_key(struct ieee80211_hw *hw, enum set_key_cmd cmd,
 	 * 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;

drivers/net/wireless/rt2x00/rt61pci.c

@@ -381,7 +381,7 @@ static int rt61pci_config_shared_key(struct rt2x00_dev *rt2x00dev,
 		if (reg && reg == mask)
 			return -ENOSPC;
 
-		key->hw_key_idx += reg ? (ffz(reg) - 1) : 0;
+		key->hw_key_idx += reg ? ffz(reg) : 0;
 
 		/*
 		 * Upload key to hardware
@@ -477,7 +477,7 @@ static int rt61pci_config_pairwise_key(struct rt2x00_dev *rt2x00dev,
 				return -ENOSPC;
 		}
 
-		key->hw_key_idx += reg ? (ffz(reg) - 1) : 0;
+		key->hw_key_idx += reg ? ffz(reg) : 0;
 
 		/*
 		 * Upload key to hardware

drivers/net/wireless/rt2x00/rt73usb.c

@@ -393,7 +393,7 @@ static int rt73usb_config_shared_key(struct rt2x00_dev *rt2x00dev,
 		if (reg && reg == mask)
 			return -ENOSPC;
 
-		key->hw_key_idx += reg ? (ffz(reg) - 1) : 0;
+		key->hw_key_idx += reg ? ffz(reg) : 0;
 
 		/*
 		 * Upload key to hardware
@@ -494,7 +494,7 @@ static int rt73usb_config_pairwise_key(struct rt2x00_dev *rt2x00dev,
 				return -ENOSPC;
 		}
 
-		key->hw_key_idx += reg ? (ffz(reg) - 1) : 0;
+		key->hw_key_idx += reg ? ffz(reg) : 0;
 
 		/*
 		 * Upload key to hardware