powerpc/cell/axon_msi: Fix refcount leak in setup_msi_msg_address

of_get_next_parent() returns a node pointer with refcount incremented,
we should use of_node_put() on it when not need anymore.
Add missing of_node_put() in the error path to avoid refcount leak.

Fixes: ce21b3c9648a ("[CELL] add support for MSI on Axon-based Cell systems")
Signed-off-by: Miaoqian Lin <[e-mail]>
Signed-off-by: Michael Ellerman <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

arch/powerpc/platforms/cell/axon_msi.c

···
 	if (!prop) {
 		dev_dbg(&dev->dev,
 			"axon_msi: no msi-address-(32|64) properties found\n");
+		of_node_put(dn);
 		return -ENOENT;
 	}