azure-sdk: Add NOLINT comments to stop clang-tidy errors

`clang-tidy` is throwing errors as it is finding potential
memory leaks in individual functions, however both
`iot_ntp_client.c` and `socketio_openiot.c` rely on the user
calling the relevant functions to free memory that has been
allocated. Only when there is an error will memory be free'd
automatically.

Signed-off-by: Jack Styles <jack.styles@arm.com>