watchdog: versal: Add support for basic window watchdog

Existing driver uses generic watchdog mode which generates a signal to
PLM firmware, but the signal cannot be used to reset the system.

Change driver to use window watchdog basic mode. This window watchdog mode
generates a signal to PLM firmware which decides what action to take upon
expiry of watchdog.

Timeout value for xlnx_wwdt_start will come in milli seconds from wdt
framework. Make changes to load count value accordingly.

Add checks before loading the timer for min and max possible values.

Fix authour email id of Ashok Reddy Soma to long email id.

Signed-off-by: Ashok Reddy Soma <ashok.reddy.soma@xilinx.com>
Link: https://lore.kernel.org/r/1632808919-8600-2-git-send-email-ashok.reddy.soma@xilinx.com


Signed-off-by: Michal Simek <michal.simek@xilinx.com>