iio: si7005: add support for Hoperf th02

This patch adds support for Hoperf th02 humidity and
temperature sensor as it uses same register definitions
as si7005

th02 Datasheet: http://www.anglia-live.com/netalogue/pdfs/hrf/datasheets/TH02_V1.1.pdf



Signed-off-by: Cristina Moraru <cristina.moraru09@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>