Need add transport length check libspdm_mctp_encode_message()

[jyao1]

In libspdm_pci_doe_encode_message(), there is length check for *transport_message_size. But the code is missing in libspdm_mctp_encode_message().

    LIBSPDM_ASSERT(*transport_message_size >=
                   aligned_message_size + sizeof(pci_doe_data_object_header_t));
    if (*transport_message_size <
        aligned_message_size + sizeof(pci_doe_data_object_header_t)) {
        *transport_message_size = aligned_message_size +
                                  sizeof(pci_doe_data_object_header_t);
        return LIBSPDM_STATUS_BUFFER_TOO_SMALL;
    }