dm: core: Use debug() instead of printf() for failures

To avoid bloating SPL code, use debug() where possible in the driver model
core code. The error code is already returned, and can be investigated as
needed.

Signed-off-by: Simon Glass <sjg@chromium.org>

drivers/core/lists.c

@@ -86,12 +86,12 @@ int device_bind_driver_to_node(struct udevice *parent, const char *drv_name,
 
 	drv = lists_driver_lookup_name(drv_name);
 	if (!drv) {
-		printf("Cannot find driver '%s'\n", drv_name);
+		debug("Cannot find driver '%s'\n", drv_name);
 		return -ENOENT;
 	}
 	ret = device_bind(parent, drv, dev_name, NULL, node, devp);
 	if (ret) {
-		printf("Cannot create device named '%s' (err=%d)\n",
+		debug("Cannot create device named '%s' (err=%d)\n",
 		      dev_name, ret);
 		return ret;
 	}