hwmon: Fix unchecked return status, batch 2

Fix up some hwmon drivers so that they no longer ignore return status
from device_create_file().
Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>