I think the CY8C4147AZI_S455 architecture is different from what you give .For CY8C4147AZI_S455 ,WDT0 is a additional timer.Show as bellow:
If I want to use the watchdog timer for against system crashes and the WDT0 for a periodic interrupt How should I configure the WDT0 ? Both the watchdog timer and the WDT0 used the same interrupt vector?
You can refer to the attached project. (Change the device in device selector)