In the current driver, the longest time of the watchdog timeout is ~8
seconds because the pre-scalar is fixed at 32 (WDCP=5). This commit
removes this limitation by dynamically calculating the pre-scalar
according to the watchdog timeout setting from the API.
Signed-off-by: Jun Lin <CHLin56@nuvoton.com>
Signed-off-by: Tom Chang <CHChang19@nuvoton.com>