rt2x00: only set TXDONE_FALLBACK in rt2800pci if the frame was retried

TXDONE_FALLBACK expresses that fallback rates were used for retries. Hence,
it only makes sense to set the flag if retries > 0.

Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>
Acked-by: Gertjan van Wingerde <gwingerde@gmail.com>
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rt2x00/rt2800pci.c

@@ -903,8 +903,12 @@ static void rt2800pci_txdone(struct rt2x00_dev *rt2x00dev)
 			txdesc.retry = 7;
 		}
 
-		__set_bit(TXDONE_FALLBACK, &txdesc.flags);
-
+		/*
+		 * the frame was retried at least once
+		 * -> hw used fallback rates
+		 */
+		if (txdesc.retry)
+			__set_bit(TXDONE_FALLBACK, &txdesc.flags);
 
 		rt2x00pci_txdone(entry, &txdesc);
 	}