open-iotsdk: Update to the latest version

The new version of the Open IoT SDK requires the following
changes in Total Solutions due to updated components:

* Update coreMQTT-Agent to the version that uses MQTT 3.1.1 as
  the aws-iot-device-sdk-embedded-c component now uses MQTT 3.1.1
* Add the required compiler definition for coreMQTT-Agent to indicate
  that the project is not using custom configuration.
* Add an additional ml-embedded-evaluation-kit include directory
  to find a header file needed by the latest version
* Change pointer from pointer to const to const pointer as the API of
  the ml-embedded-evaluation-kit for `ethosu_init()` has changed
* Increase MQTT timeout periods for the AWS OTA demo as the
  AVH simulation runs faster with the new version of the Open IoT SDK

Signed-off-by: Hugues Kamba-Mpiana <hugues.kambampiana@arm.com>