iio: tmp007: Fix `name` attribute ABI

The IIO ABI specifies the name field of the IIO device as:

	Description of the physical chip / device for device X.
	Typically a part number.

The tmp007 driver currently uses the name of the parent device instead.
Change this to the part name to be in accordance with the ABI.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>