core: drop const for struct driver_info

In order to prepare for a new support of phandle when OF_PLATDATA is used
drop the const for struct driver_info as this struct will need to be
updated on runtime.

Signed-off-by: Walter Lozano <walter.lozano@collabora.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/core/root.c b/drivers/core/root.c
index 7d257ea..23a65cd 100644
--- a/drivers/core/root.c
+++ b/drivers/core/root.c
@@ -26,7 +26,7 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
-static const struct driver_info root_info = {
+static struct driver_info root_info = {
 	.name		= "root_driver",
 };