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>

iio: accel: Add driver support for ADXL313

ADXL313 is a small, thin, low power, 3-axis accelerometer with high
resolution measurement up to +/-4g. It includes an integrated 32-level
FIFO and has activity and inactivity sensing capabilities.

Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ADXL313.pdf
Signed-off-by: Lucas Stankus <lucas.p.stankus@gmail.com>
Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/d16e2d1967e46bb2b1024b6d23bc4889da77dc6b.1630523106.git.lucas.p.stankus@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>