iio: imu: add BNO055 serdev driver

Add a serdev driver for communicating to a BNO055 IMU via serial bus, and
enable the BNO055 core driver to work in this scenario.

Signed-off-by: Andrea Merello <andrea.merello@iit.it>
Link: https://lore.kernel.org/r/20220907132205.28021-13-andrea.merello@iit.it
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>