PCI: dwc: layerscape: Fix a leaked reference by adding missing of_node_put()

The call to of_parse_phandle() returns a node pointer with refcount
incremented thus it must be explicitly decremented after the last
usage.

Detected by coccinelle with the following warnings:
./drivers/pci/controller/dwc/pci-layerscape.c:204:1-7: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 198, but without a corresponding object release within this function.

Signed-off-by: Wen Yang <[e-mail]>
Signed-off-by: Lorenzo Pieralisi <[e-mail]>
Cc: Minghuan Lian <[e-mail]>
Cc: Mingkai Hu <[e-mail]>
Cc: Roy Zang <[e-mail]>
Cc: Lorenzo Pieralisi <[e-mail]>
Cc: Bjorn Helgaas <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]

drivers/pci/controller/dwc/pci-layerscape.c

···
 		return -EINVAL;
 	}
 
+	of_node_put(msi_node);
 	return 0;
 }