hwmon: (corsair-psu) fix possible out-of-bounds access on missing string termination

hwmon: (corsair-psu) fix possible out-of-bounds access on missing string termination

In theory it could be possible that the REPLY_SIZE sized buffers for
holding the vendor and product strings could be end up missing the null
termination (for example by malicious hardware built on purpose)
required by the seq_printf() call. That limits the debugfs printf calls
to a maximum string length of REPLY_SIZE.

Fixes: d115b51e0e567 ("hwmon: add Corsair PSU HID controller driver")
Signed-off-by: Wilken Gottwalt <wilken.gottwalt@posteo.net>
Link: https://lore.kernel.org/r/anLj9gPWRoRDbQBV@monster.localdomain
Signed-off-by: Guenter Roeck <linux@roeck-us.net>