PCI: rpadlpar: Use for_each_child_of_node() and for_each_node_by_name()

Use for_each_child_of_node() and for_each_node_by_name() macros instead of
open coding them.

Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Qinglang Miao <[e-mail]>
Signed-off-by: Bjorn Helgaas <[e-mail]>

drivers/pci/hotplug/rpadlpar_core.c

···
 static struct device_node *find_vio_slot_node(char *drc_name)
 {
 	struct device_node *parent = of_find_node_by_name(NULL, "vdevice");
-	struct device_node *dn = NULL;
+	struct device_node *dn;
 	int rc;
 
 	if (!parent)
 		return NULL;
 
-	while ((dn = of_get_next_child(parent, dn))) {
+	for_each_child_of_node(parent, dn) {
 		rc = rpaphp_check_drc_props(dn, drc_name, NULL);
 		if (rc == 0)
 			break;
···
 static struct device_node *find_php_slot_pci_node(char *drc_name,
 						  char *drc_type)
 {
-	struct device_node *np = NULL;
+	struct device_node *np;
 	int rc;
 
-	while ((np = of_find_node_by_name(np, "pci"))) {
+	for_each_node_by_name(np, "pci") {
 		rc = rpaphp_check_drc_props(np, drc_name, drc_type);
 		if (rc == 0)
 			break;