sfc: Fail self-test with -EBUSY, not -EIO, if the device is busy

Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NShradha Shah <sshah@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/sfc/ethtool.c

@@ -461,7 +461,7 @@ static void efx_ethtool_self_test(struct net_device *net_dev,
 		goto fail;
 
 	if (efx->state != STATE_READY) {
-		rc = -EIO;
+		rc = -EBUSY;
 		goto out;
 	}