watchdog: fix compiler error for missing parenthesis

Joe's patch(watchdog: Use pr_<fmt> and pr_<level>) missed parenthesis in s3c2410_wdt.c.

Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>