dpaa2-ptp: defer probe when portal allocation failed

The fsl_mc_portal_allocate can fail when the requested MC portals are
not yet probed by the fsl_mc_allocator. In this situation, the driver
should defer the probe.
Signed-off-by: NIoana Ciornei <ioana.ciornei@nxp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/freescale/dpaa2/dpaa2-ptp.c

@@ -140,7 +140,10 @@ static int dpaa2_ptp_probe(struct fsl_mc_device *mc_dev)
 
 	err = fsl_mc_portal_allocate(mc_dev, 0, &mc_dev->mc_io);
 	if (err) {
-		dev_err(dev, "fsl_mc_portal_allocate err %d\n", err);
+		if (err == -ENXIO)
+			err = -EPROBE_DEFER;
+		else
+			dev_err(dev, "fsl_mc_portal_allocate err %d\n", err);
 		goto err_exit;
 	}