dap: add CMSIS-DAP compatible controller

Add CMSIS-DAP compatible controller which is a handler between
the host interface and SWD driver. The controller follows CMSIS-DAP
reference implementation. It expects a request buffer from the host
interface, splits it to simple transfers and forwards to the DP driver,
and finally returns a response buffer to the host.
Interface to the host can be implemented with USB HID device support.

Controller implements only SW-DP support and is tested
with pyOCD and ADIv5.x.

Signed-off-by: Johann Fischer <j.fischer@phytec.de>