[WATCHDOG] doc: Fix use of WDIOC_SETOPTIONS ioctl.

In the watchdog-test program and watchdog-api.txt, pass the values to
the WDIOC_SETOPTIONS ioctl as a pointer to an integer containing the
values intead of directly in the third ioctl argument. The actual
watchdog drivers in drivers/watchdog don't read the options directly
from the argument but use get_user and copy_from_user.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>