dm: core: Avoid calling dm_scan_fdt_dev() with of-platdata

We cannot call dm_scan_fdt_dev() with of-platdata since there is no device
tree. Fix this with an #if check.

Fixes: 3be9a37 (dm: syscon: scan sub-nodes of the syscon node)
Signed-off-by: Simon Glass <sjg@chromium.org>

drivers/core/syscon-uclass.c

@@ -104,5 +104,8 @@ static const struct udevice_id generic_syscon_ids[] = {
 U_BOOT_DRIVER(generic_syscon) = {
 	.name	= "syscon",
 	.id	= UCLASS_SYSCON,
+#if !CONFIG_IS_ENABLED(OF_PLATDATA)
+	.bind           = dm_scan_fdt_dev,
+#endif
 	.of_match = generic_syscon_ids,
 };