iio: temp: maxim thermocouple: Drop unneeded semi colon.

Identified by coccinelle

CHECK   drivers/iio/temperature/maxim_thermocouple.c
drivers/iio/temperature/maxim_thermocouple.c:197:3-4: Unneeded semicolon

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Matt Ranostay <matt.ranostay@konsulko.com>