[WATCHDOG] w836?7hf_wdt spinlock fixes.

Add io spinlocks to prevent possible race
conditions between start and stop operations
that are issued from different child processes
where the master process opened /dev/watchdog.

Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

diff --cc drivers/char/watchdog/w83627hf_wdt.c
Simple merge

diff --cc drivers/char/watchdog/w83697hf_wdt.c
Simple merge