Watchdog: Add marvell GTI watchdog driver

This patch add support for Marvell GTI watchdog.  Global timer
unit (GTI) support hardware watchdog timer. Software programs
watchdog timer to generate interrupt on first timeout, second
timeout is configured to be ignored and system reboots on
third timeout.

Signed-off-by: Bharat Bhushan <bbhushan2@marvell.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20230803032523.6242-2-bbhushan2@marvell.com
[groeck: MODULE_LICENSE GPL v2 -> GPL since that is sufficient]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>