sfc: EFX_WORKAROUND_ALWAYS is really specific to Falcon-architecture

The workarounds that currently use EFX_WORKAROUND_ALWAYS are in
Falcon-specific or Falcon-arch-specific code, so get rid of the
conditions altogether.  Add/move comments as appropriate.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
diff --git a/drivers/net/ethernet/sfc/farch.c b/drivers/net/ethernet/sfc/farch.c
index c3d07c5..7f50882 100644
--- a/drivers/net/ethernet/sfc/farch.c
+++ b/drivers/net/ethernet/sfc/farch.c
@@ -830,8 +830,7 @@
 		netif_tx_lock(efx->net_dev);
 		efx_farch_notify_tx_desc(tx_queue);
 		netif_tx_unlock(efx->net_dev);
-	} else if (EFX_QWORD_FIELD(*event, FSF_AZ_TX_EV_PKT_ERR) &&
-		   EFX_WORKAROUND_10727(efx)) {
+	} else if (EFX_QWORD_FIELD(*event, FSF_AZ_TX_EV_PKT_ERR)) {
 		efx_schedule_reset(efx, RESET_TYPE_TX_DESC_FETCH);
 	} else {
 		netif_err(efx, tx_err, efx->net_dev,
@@ -1531,8 +1530,7 @@
 	}
 
 	if (queues != 0) {
-		if (EFX_WORKAROUND_15783(efx))
-			efx->irq_zero_count = 0;
+		efx->irq_zero_count = 0;
 
 		/* Schedule processing of any interrupting queues */
 		if (likely(soft_enabled)) {
@@ -1544,9 +1542,11 @@
 		}
 		result = IRQ_HANDLED;
 
-	} else if (EFX_WORKAROUND_15783(efx)) {
+	} else {
 		efx_qword_t *event;
 
+		/* Legacy ISR read can return zero once (SF bug 15783) */
+
 		/* We can't return IRQ_HANDLED more than once on seeing ISR=0
 		 * because this might be a shared interrupt. */
 		if (efx->irq_zero_count++ == 0)