dm: Use uclass_first_device_err() where it is useful

Use this new function in places where it simplifies the code.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/video/vidconsole-uclass.c b/drivers/video/vidconsole-uclass.c
index 832e90a..c8cc05e 100644
--- a/drivers/video/vidconsole-uclass.c
+++ b/drivers/video/vidconsole-uclass.c
@@ -240,8 +240,7 @@
 	if (argc != 3)
 		return CMD_RET_USAGE;
 
-	uclass_first_device(UCLASS_VIDEO_CONSOLE, &dev);
-	if (!dev)
+	if (uclass_first_device_err(UCLASS_VIDEO_CONSOLE, &dev))
 		return CMD_RET_FAILURE;
 	col = simple_strtoul(argv[1], NULL, 10);
 	row = simple_strtoul(argv[2], NULL, 10);
@@ -259,8 +258,7 @@
 	if (argc != 2)
 		return CMD_RET_USAGE;
 
-	uclass_first_device(UCLASS_VIDEO_CONSOLE, &dev);
-	if (!dev)
+	if (uclass_first_device_err(UCLASS_VIDEO_CONSOLE, &dev))
 		return CMD_RET_FAILURE;
 	for (s = argv[1]; *s; s++)
 		vidconsole_put_char(dev, *s);