Add BMI270 Driver Functionality to Zephyr

[ljunquera]

Is there a way to add this driver functionality to The Zephyr Project. There is an enhancement request for it, but it would be great to have it supported by Bosch. Specifically I am looking for:

1. activity change recognition (still, walking, running)
2. wrist gestures (push arm down, pivot up, wrist shake jiggle, flick in, flick out, wrist wear wake up)
3. context (step counter and step detector, activity change recognition, still, walking, running)