dm: core: Convert driver_bind() to use const

The driver is not modified by driver model, so update driver_bind() to
recognise that.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Marek Vasut <marex@denx.de>
diff --git a/drivers/core/device-remove.c b/drivers/core/device-remove.c
index 3a5f48d..7fee1c0 100644
--- a/drivers/core/device-remove.c
+++ b/drivers/core/device-remove.c
@@ -66,7 +66,7 @@
 
 int device_unbind(struct udevice *dev)
 {
-	struct driver *drv;
+	const struct driver *drv;
 	int ret;
 
 	if (!dev)
@@ -139,7 +139,7 @@
 
 int device_remove(struct udevice *dev)
 {
-	struct driver *drv;
+	const struct driver *drv;
 	int ret;
 
 	if (!dev)