dm: video: sandbox: Convert sandbox to use driver model for video

Now that driver model support is available, convert sandbox over to use it.
We can remove a few of the special hooks that sandbox currently has.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Anatolij Gustschin <agust@denx.de>
diff --git a/drivers/serial/sandbox.c b/drivers/serial/sandbox.c
index cd2f91e..45dff98 100644
--- a/drivers/serial/sandbox.c
+++ b/drivers/serial/sandbox.c
@@ -16,6 +16,7 @@
 #include <lcd.h>
 #include <os.h>
 #include <serial.h>
+#include <video.h>
 #include <linux/compiler.h>
 #include <asm/state.h>
 
@@ -114,9 +115,7 @@
 		return 0;
 
 	os_usleep(100);
-#ifdef CONFIG_LCD
-	lcd_sync();
-#endif
+	video_sync_all();
 	if (next_index == serial_buf_read)
 		return 1;	/* buffer full */