[WATCHDOG] ks8695_wdt.c: 'CLOCK_TICK_RATE' undeclared

On arm-acs5k_tiny:

drivers/watchdog/ks8695_wdt.c:68: error: 'CLOCK_TICK_RATE' undeclared
	(first use in this function)

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Cc: stable <stable@kernel.org>