regulator: mc13xxx: Fix NULL pointer error in non-DT mode

Add a check to avoid NULL pointer dereference error when
booted in non-DT mode. While at it also remove the additional
of_node_get which is no longer needed for of_get_child_by_name
and fix the node pointer.

Signed-off-by: Sachin Kamat <[e-mail]>
Reported-by: Philippe Rétornaz <[e-mail]>
Signed-off-by: Mark Brown <[e-mail]>

drivers/regulator/mc13xxx-regulator-core.c

···
 	struct device_node *parent;
 	int num;
 
-	of_node_get(pdev->dev.parent->of_node);
-	parent = of_get_child_by_name(pdev->dev.parent->of_node, "regulators");
+	if (!pdev->dev.of_node)
+		return -ENODEV;
+
+	parent = of_get_child_by_name(pdev->dev.of_node, "regulators");
 	if (!parent)
 		return -ENODEV;
 
···
 	struct device_node *parent, *child;
 	int i, parsed = 0;
 
-	of_node_get(pdev->dev.parent->of_node);
-	parent = of_get_child_by_name(pdev->dev.parent->of_node, "regulators");
+	if (!pdev->dev.of_node)
+		return NULL;
+
+	parent = of_get_child_by_name(pdev->dev.of_node, "regulators");
 	if (!parent)
 		return NULL;