commit adfa9698 upstream.

The value sent on the SPI bus is shifted by an erroneous number of bits.
The shift value was already computed in the iio_chan_spec structure and
hence subtracting this argument to 16 yields an erroneous data position
in the SPI stream.
Signed-off-by: JM Friedt <jmfriedt@femto-st.fr>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>