powerpc/kexec_file: add missing of_node_put

for_each_node_with_property performs an of_node_get on each
iteration, so a break out of the loop requires an
of_node_put.

This was done using the Coccinelle semantic patch
iterators/for_each_child.cocci
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230907095521.14053-7-Julia.Lawall@inria.fr

arch/powerpc/kexec/file_load_64.c

@@ -1138,11 +1138,15 @@ static int update_pci_dma_nodes(void *fdt, const char *dmapropname)
 			continue;
 
 		ret = copy_property(fdt, pci_offset, dn, "ibm,dma-window");
-		if (ret < 0)
+		if (ret < 0) {
+			of_node_put(dn);
 			break;
+		}
 		ret = copy_property(fdt, pci_offset, dn, dmapropname);
-		if (ret < 0)
+		if (ret < 0) {
+			of_node_put(dn);
 			break;
+		}
 	}
 
 	return ret;