iio: adis16480: support burst read function

iio: adis16480: support burst read function

Some supported devices support burst read function. This provides a method
for reading a batch of data (status, temperature, gyroscopes,
accelerometers, time stamp/data counter, and CRC code), which does not
require a stall time between each 16-bit segment and only requires one
command on the DIN line to initiate. Devices supporting this mode
are:

 * adis16495-1
 * adis16495-2
 * adis16495-3
 * adis16497-1
 * adis16497-2
 * adis16497-3

Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20210422103735.136367-1-nuno.sa@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>