drivers/lis2dux12: add read_and_decode APIs support

Add RTIO async and RTIO stream functionalities that enables,
among all the other things, the sensor data streaming from FIFO.

RTIO stream supports following triggers:

  - SENSOR_TRIG_FIFO_WATERMARK
  - SENSOR_TRIG_FIFO_FULL
  - SENSOR_TRIG_DATA_READY

Following FIFO parameters has to be defined in device tree to
correctly stream sensor data:

  - fifo-watermark
  - accel-fifo-batch-rate

Currently the driver can decode FIFO content with Accelerometer
16-bit samples.

Signed-off-by: Armando Visconti <armando.visconti@st.com>