BMI270 acc support

Just the accelerometer for now.

It doesn't implement its own data retrieval task, so calling it from Python is a synchronous I2C transaction. Can be optimized later.

components/bmi270/bmi270_context_examples/accel/Makefile

+COINES_INSTALL_PATH ?= ../../../..
+
+EXAMPLE_FILE ?= accel.c
+
+API_LOCATION ?= ../..
+
+COMMON_LOCATION ?= ..
+
+C_SRCS += \
+$(API_LOCATION)/bmi2.c \
+$(API_LOCATION)/bmi270_context.c \
+$(COMMON_LOCATION)/common/common.c
+
+INCLUDEPATHS += \
+$(API_LOCATION) \
+$(COMMON_LOCATION)/common
+
+include $(COINES_INSTALL_PATH)/coines.mk
\ No newline at end of file