boot: cedit: include u-boot/schedule.h

This TU currently relies on getting a declaration of schedule()
through some nested include. Include the proper header directly.

Signed-off-by: Rasmus Villemoes <ravi@prevas.dk>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Stefan Roese <sr@denx.de>

boot/cedit.c

@@ -20,6 +20,7 @@
 #include <video.h>
 #include <linux/delay.h>
 #include "scene_internal.h"
+#include <u-boot/schedule.h>
 
 enum {
 	CMOS_MAX_BITS	= 2048,