Bluetooth: btqcomsmd: retrieve BD address from DT property

Retrieve BD address from the local-bd-address property.
This address must be unique and is usually added in the DT
by the bootloader which has access to the provisioned data.

Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
(cherry picked from commit f5f3dc0abf8baa7dfbdb2e0720e9a3d221a67ea9)