led: Move OF "label" property parsing to core

Every driver in drivers/led/ currently does some form of "label" OF
property parsing in its bind() callback. Move this label parsing to
LED core, since this "label" OF property is a generic property. This
permits code deduplication in subseuqent patches.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Alex Nemirovsky <alex.nemirovsky@cortina-access.com>
Cc: Patrick Delaunay <patrick.delaunay@foss.st.com>
Cc: Philippe Reynes <philippe.reynes@softathome.com>
Cc: Sean Anderson <seanga2@gmail.com>
Cc: Simon Glass <sjg@chromium.org>
Cc: Steven Lawrance <steven.lawrance@softathome.com>
diff --git a/drivers/led/led-uclass.c b/drivers/led/led-uclass.c
index 7e298db..2f4aa18 100644
--- a/drivers/led/led-uclass.c
+++ b/drivers/led/led-uclass.c
@@ -95,8 +95,20 @@
 	return ret;
 }
 
+static int led_post_bind(struct udevice *dev)
+{
+	struct led_uc_plat *uc_plat = dev_get_uclass_plat(dev);
+
+	uc_plat->label = dev_read_string(dev, "label");
+	if (!uc_plat->label)
+		uc_plat->label = ofnode_get_name(dev_ofnode(dev));
+
+	return 0;
+}
+
 UCLASS_DRIVER(led) = {
 	.id		= UCLASS_LED,
 	.name		= "led",
 	.per_device_plat_auto	= sizeof(struct led_uc_plat),
+	.post_bind	= led_post_bind,
 };