gianfar: Fix potential soft reset race

SOFT_RESET must be asserted for at least 3 TX clocks in order for it to work
properly.  The syncs in the gfar_write() commands have been hiding this, but
we need to guarantee it.
Signed-off-by: Andy Fleming <afleming@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/gianfar.c

@@ -351,6 +351,9 @@ static int gfar_probe(struct of_device *ofdev,
 	/* Reset MAC layer */
 	gfar_write(&priv->regs->maccfg1, MACCFG1_SOFT_RESET);
 
+	/* We need to delay at least 3 TX clocks */
+	udelay(2);
+
 	tempval = (MACCFG1_TX_FLOW | MACCFG1_RX_FLOW);
 	gfar_write(&priv->regs->maccfg1, tempval);