watchdog: apple: set max_hw_heartbeat_ms instead of max_timeout

The hardware only supports timeouts slightly below 3mins, but by using
max_hw_heartbeat_ms we can let the kernel take care of supporting larger
timeouts than that requested from userspace.

Switching to max_hw_heartbeat_ms also means our set_timeout function now
needs to configure the hardware to the minimum of either the requested
timeout (in seconds) or the maximum supported by the user (in seconds).

Signed-off-by: Florian Klink <flokli@flokli.de>
Reviewed-by: Wim Van Sebroeck <wim@linux-watchdog.org>
Link: https://lore.kernel.org/r/20250506142621.11428-2-flokli@flokli.de


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