watchdog: s3c2410_wdt: Fix max_timeout being calculated larger

watchdog: s3c2410_wdt: Fix max_timeout being calculated larger

Fix the issue of max_timeout being calculated larger than actual value.
The calculation result of freq / (S3C2410_WTCON_PRESCALE_MAX + 1) /
S3C2410_WTCON_MAXDIV is smaller than the actual value because the remainder
is discarded during the calculation process. This leads to a larger
calculated value for max_timeout compared to the actual settable value.
To resolve this issue, the order of calculations in the computation process
has been adjusted.

Reviewed-by: Sam Protsenko <semen.protsenko@linaro.org>
Signed-off-by: Sangwook Shin <sw617.shin@samsung.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>