dt-bindings:iio:temperature:melexis,mlx90614 yaml conversion

Simple conversion from txt to yaml.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Crt Mori <cmo@melexis.com>
Cc: Peter Meerwald <pmeerw@pmeerw.net>
Link: https://lore.kernel.org/r/20201031134110.724233-25-jic23@kernel.org