dm: video: Fix cache flushes

Content can come to screen via putc() and we cannot always rely on
updates ending with a puts().  This is the case with efi_console output
to vidconsole.  Fixes corruption with Shell.efi.

Signed-off-by: Rob Clark <robdclark@gmail.com>

drivers/video/vidconsole-uclass.c

@@ -163,6 +163,7 @@ static void vidconsole_putc(struct stdio_dev *sdev, const char ch)
 	struct udevice *dev = sdev->priv;
 
 	vidconsole_put_char(dev, ch);
+	video_sync(dev->parent);
 }
 
 static void vidconsole_puts(struct stdio_dev *sdev, const char *s)
@@ -260,6 +261,8 @@ static int do_video_puts(cmd_tbl_t *cmdtp, int flag, int argc,
 	for (s = argv[1]; *s; s++)
 		vidconsole_put_char(dev, *s);
 
+	video_sync(dev->parent);
+
 	return 0;
 }