hwmon: Clean up detect functions

As kind is now hard-coded to -1, there is room for code clean-ups.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Corentin Labbe <corentin.labbe@geomatys.fr>
Cc: "Mark M. Hoffman" <mhoffman@lightlink.com>
Cc: Juerg Haefliger <juergh@gmail.com>
Cc: Riku Voipio <riku.voipio@iki.fi>
Acked-by: "Hans J. Koch" <hjk@linutronix.de>
Cc: Rudolf Marek <r.marek@assembler.cz>