Adding BMI270 Support

[t-morisawa]

I'm developing a driver of BMI270.

Datasheet: https://www.bosch-sensortec.com/media/boschsensortec/downloads/datasheets/bst-bmi270-ds000.pdf

The IMU is used in M5Stack Core2 1.3.
ref: https://docs.m5stack.com/en/core/Core2_v1.3