staging:iio: Fix adis16220 channel offsets and scales

Most of the channel offsets and scales in the adis16220 are incorrect:
	* Temperature scale is off by a factor of 1000
	* Voltage scale is off by a factor of 1000
	* Acceleration seems to have a typo "187042" since it should be instead of
	  "1887042"
	* Temperature offset is completely wrong

This patch fixes these issues.

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