iio: Fix misspellings of "Analog Devices"

According to https://www.analog.com/

, the company name is spelled
"Analog Devices".

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>