Fix alias pointer passing bug.

  In xC if a function argument is restricted pointer and the function
  accesses a global then you cannot pass a non-local alias pointer
  (e.g. an alias pointer to a global). This is because the pointer then
  may alias the global accessed in the function (which it shouldn't since
  it is a restricted pointer.

  This is happening in the code where a pointer to a global is taken:

     avb_1722_1_acmp_inflight_command *inflight =
        &acmp_listener_inflight_commands[i];

  and then this is passed into a function that accesses a global:

     acmp_send_command(... &inflight->command ...);

  This commit fixes this by explictly marking the parameter to
  acmp_send_command as aliased. The 13.0.0 compiler has a bug which means
  it does not spot this error yet but this fix is to safeguard the code when
  the compiler is fixed.