[Pi 3B (Non-Plus) / Pi Zero W ONLY]
As of kernel package, linux-raspberrypi-4.14.59-1, support for notifying the kernel of the
Broadcom bluetooth device through the device tree has been enabled.
There is no longer a need for btattach, which makes the lives of everyone
easier. There is also no need to fall back to hciattach for better performance, as the