watchdog: it87_wdt: Remove redundant max_units setting

Commit 893dc8b5 ("watchdog: it87: Drop support for resetting watchdog
though CIR and Game port") removed the try_gameport variable, and left
max_units setting redundant.

To clean up the code, this patch removes this redundant setting.

Signed-off-by: Werner Fischer <devlists@wefi.net>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20231213094525.11849-2-devlists@wefi.net


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