watchdog.h: change include of cyclic.h to u-boot/schedule.h

watchdog.h: change include of cyclic.h to u-boot/schedule.h

Nobody relies on getting the cyclic API declared by including the
watchdog.h header, but for historical reasons, many TUs include
watchdog.h to get a declaration of schedule(). Now that we have a
dedicated header for just that, include that header instead of
cyclic.h.

Eventually, all TUs that call schedule() should themselves include
u-boot/schedule.h, but this is a step towards getting rid of
unnecessary include statements in cyclic.h and global_data.h.

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