net: fman: memac: free mdio device if lynx_pcs_create() fails

When memory allocation fails in lynx_pcs_create() and it returns NULL,
there remains a dangling reference to the mdiodev returned by
of_mdio_find_device() which is leaked as soon as memac_pcs_create()
returns empty-handed.

Fixes: a7c2a32e7f22 ("net: fman: memac: Use lynx pcs driver")
Signed-off-by: Vladimir Oltean <[e-mail]>
Reviewed-by: Sean Anderson <[e-mail]>
Acked-by: Madalin Bucur <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

drivers/net/ethernet/freescale/fman/fman_memac.c

···
 		return ERR_PTR(-EPROBE_DEFER);
 
 	pcs = lynx_pcs_create(mdiodev);
+	if (!pcs)
+		mdio_device_free(mdiodev);
+
 	return pcs;
 }