drivers: iio: accel: adxl312 and adxl314 support

ADXL312 and ADXL314 are small, thin, low power, 3-axis accelerometers
with high resolution (13-bit) measurement up to +/-12 g and +/- 200 g
respectively.

Implement support for ADXL312 and ADXL314 by extending the ADXL313
driver.

Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ADXL312.pdf
Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ADXL314.pdf


Signed-off-by: George Mois <george.mois@analog.com>
Link: https://lore.kernel.org/r/20220905132018.364900-2-george.mois@analog.com


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>