The DTLS server is running in Zephyr and is listening on port 4242
and when it receives DTLS UDP packet, it will reverse the data and
send it back to the caller.
Use the dtls-client application running in host to connect to
the dtls-server.
Change-Id: I3306cb242498019ffc9e0519b06061c36db96f78
Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>