dt-bindings: net: add TI CC2560 Bluetooth chip

This adds a compatible string for the Texas Instruments CC2560 Bluetooth
chip to the existing TI WiLink shared transport bindings. These chips are
similar enough that the same bindings work for both. The file is renamed
to ti-bluetooth.txt to make it more generic.

Signed-off-by: David Lechner <david@lechnology.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>