Cleanup for P2P tests 817 and 819

[sunnywang-arm]

P2P (Peer-to-Peer) rules in BSA spec are conditional requirements and only applicable when the system supports P2P. Since there is no way for test suite to know if system supports P2P, using -p2p option with bsa-acs is required for users to run the P2P tests.

For tests 817 and 819, there is no message about using -p2p option. Also, test 817 is always executed regardless of P2P support. Therefore, I think we need to add the code block below to both tests.

  /* Check If PCIe Hierarchy supports P2P */
  if (val_pcie_p2p_support() == NOT_IMPLEMENTED) {
    val_print(ACS_PRINT_DEBUG, "\n       The test is applicable only if the system supports", 0);
    val_print(ACS_PRINT_DEBUG, "\n       P2P traffic. If the system supports P2P, pass the", 0);
    val_print(ACS_PRINT_DEBUG, "\n       command line option '-p2p' while running the binary", 0);
    val_set_status(pe_index, RESULT_SKIP(TEST_NUM, 1));
    return;
  }

Also, it looks like the second val_pcie_p2p_support() code block in tests 901, 902, 818, 819 is redundant. Please check and remove them.