Bluetooth: Rename mgmt_to_le to bdaddr_to_le

Since address type macros are not only related to Management
Interface anymore, it makes sense to rename the helper function
mgmt_to_le to bdaddr_to_le.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Acked-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>