dm: pmic: Convert uclass to livetree

Update the pmic uclass and all pmics to support a live device tree.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/power/pmic/lp873x.c b/drivers/power/pmic/lp873x.c
index d8f30df..f505468 100644
--- a/drivers/power/pmic/lp873x.c
+++ b/drivers/power/pmic/lp873x.c
@@ -46,15 +46,13 @@
 
 static int lp873x_bind(struct udevice *dev)
 {
-	int regulators_node;
-	const void *blob = gd->fdt_blob;
+	ofnode regulators_node;
 	int children;
-	int node = dev_of_offset(dev);
-
-	regulators_node = fdt_subnode_offset(blob, node, "regulators");
 
-	if (regulators_node <= 0) {
-		printf("%s: %s reg subnode not found!", __func__, dev->name);
+	regulators_node = dev_read_subnode(dev, "regulators");
+	if (!ofnode_valid(regulators_node)) {
+		debug("%s: %s regulators subnode not found!", __func__,
+		      dev->name);
 		return -ENXIO;
 	}