Bluetooth: btintel: Add Device Configuration support

btintel_load_ddc_config retrieves the ddc file and sends its content
via DDC commands (opcode 0xfc8b).

The ddc file should contain one or more DDC structures.
A DDC structure is composed of the folowing fields:
field: | DDC LEN |    DDC ID    |   DDC VALUE   |
size:  | 1 byte  |    2 bytes   |  DDC LEN - 2  |

Signed-off-by: Loic Poulain <loic.poulain@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>