watchdog: xilinx_wwdt: Add Versal window watchdog support

Versal watchdog driver uses window watchdog mode. Window watchdog
timer(WWDT) contains closed(first) and open(second) window with
32 bit width. Write to the watchdog timer within predefined window
periods of time. This means a period that is not too soon and a
period that is not too late. The WWDT has to be restarted within
the open window time. If software tries to restart WWDT outside of
the open window time period, it generates a reset.

Signed-off-by: Srinivas Neeli <srinivas.neeli@amd.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lkml.kernel.org/r/20230420104231.2243079-4-srinivas.neeli@amd.com


Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>