demo: migrate uclass to livetree

Use dev_ function to read the sides and colour to support a live tree.

Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/demo/demo-uclass.c b/drivers/demo/demo-uclass.c
index 815f8de..09f9a47 100644
--- a/drivers/demo/demo-uclass.c
+++ b/drivers/demo/demo-uclass.c
@@ -10,15 +10,11 @@
 #include <dm.h>
 #include <dm-demo.h>
 #include <errno.h>
-#include <fdtdec.h>
 #include <log.h>
 #include <malloc.h>
-#include <asm/global_data.h>
 #include <asm/io.h>
 #include <linux/list.h>
 
-DECLARE_GLOBAL_DATA_PTR;
-
 UCLASS_DRIVER(demo) = {
 	.name		= "demo",
 	.id		= UCLASS_DEMO,
@@ -67,10 +63,9 @@
 int demo_parse_dt(struct udevice *dev)
 {
 	struct dm_demo_pdata *pdata = dev_get_plat(dev);
-	int dn = dev_of_offset(dev);
 
-	pdata->sides = fdtdec_get_int(gd->fdt_blob, dn, "sides", 0);
-	pdata->colour = fdt_getprop(gd->fdt_blob, dn, "colour", NULL);
+	pdata->sides = dev_read_s32_default(dev, "sides", 0);
+	pdata->colour = dev_read_string(dev, "colour");
 	if (!pdata->sides || !pdata->colour) {
 		debug("%s: Invalid device tree data\n", __func__);
 		return -EINVAL;