Allow configuring the "action" bit, as documented in [1].

Previously, the only action supported by this module was to reset the
system (0).  It can now be configured to power off (1) instead.

[1]: https://www.amd.com/system/files/TechDocs/44413.pdfSigned-off-by: Vladimir Panteleev <git@vladimir.panteleev.md>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20220920092721.7686-1-git@vladimir.panteleev.mdSigned-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>