ath9k: fix possible hang on flush

If a flush is requested, make sure to clear the descriptor once we've
processed it.

This resolves a hang that will occur if all RX descriptors are full when a
flush is requested.

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Acked-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath9k/recv.c

@@ -1113,14 +1113,13 @@ requeue_drop_frag:
 		}
 requeue:
 		list_add_tail(&bf->list, &sc->rx.rxbuf);
-		if (flush)
-			continue;
 
 		if (edma) {
 			ath_rx_edma_buf_link(sc, qtype);
 		} else {
 			ath_rx_buf_relink(sc, bf);
-			ath9k_hw_rxena(ah);
+			if (!flush)
+				ath9k_hw_rxena(ah);
 		}
 	} while (1);