Do not use hcitattach to reconfigure the baudrate but set it directly in the
Bluetooth FW file; this work arounds some synchronization problems when not
using HW flow control.
https://jira.digi.com/browse/DEL-3052https://jira.digi.com/browse/DEL-3057
Signed-off-by: Isaac Hermida <isaac.hermida@digi.com>