hostnamectl determines the chassis type in different ways depending
on whether we are running on laptop, pc, VM, container or target
hardware. This guess is not predictable.
Bluez set the class of device from the chassis type.
On a laptop or desktop chassis, BlueZ will automatically
set the Bluetooth Class of Device to "Laptop" or "Desktop" and this
is overwriting value configured in /etc/bluetooth/main.conf.
Let's statically configure the chassis type to "embedded" to avoid
Signed-off-by: Frédéric Dalleau <email@example.com>