Re-enable this particular DELAY() for now, at least until the

TX and RX PCU stop/drain routines have been thoroughly debugged.

It's also very likely that I should add hooks back up to the
interface glue (if_ath_pci / if_ath_ahb) to do any relevant
bus flushes that are required.  A WMAC DDR flush may be required
for the AR9130 SoC.

sys/dev/ath/if_ath.c

@@ -5421,7 +5421,9 @@ ath_stoprecv(struct ath_softc *sc, int dodelay)
 	 * TODO: see if this particular DELAY() is required; it may be
 	 * masking some missing FIFO flush or DMA sync.
 	 */
+#if 0
 	if (dodelay)
+#endif
 		DELAY(3000);		/* 3ms is long enough for 1 frame */
 #ifdef ATH_DEBUG
 	if (sc->sc_debug & (ATH_DEBUG_RESET | ATH_DEBUG_FATAL)) {