iio: adc: ad9467: add support for AD9265 high-speed ADC

iio: adc: ad9467: add support for AD9265 high-speed ADC

The AD9265 is a 16-bit, 125 MSPS analog-to-digital converter (ADC). The
AD9265 is designed to support communications applications where high
performance combined with low cost, small size, and versatility is
desired.

The ADC core features a multistage, differential pipelined architecture
with integrated output error correction logic to provide 16-bit accuracy at
125 MSPS data rates and guarantees no missing codes over the full operating
temperature range.

The ADC features a wide bandwidth differential sample-and-hold analog input
amplifier supporting a variety of user-selectable input ranges. It is
suitable for multiplexed systems that switch full-scale voltage levels in
successive channels and for sampling single-channel inputs at frequencies
well beyond the Nyquist rate. Combined with power and cost savings over
previously available ADCs, the AD9265 is suitable for applications in
communications, instrumentation and medical imaging.

Link: https://www.analog.com/media/en/technical-documentation/data-sheets/AD9434.pdf
The driver supports the same register set as the AD9467, so the support for
this chip is added to the 'ad9467' driver.

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20200924080518.96410-4-alexandru.ardelean@analog.com