[HIP Support] Template variable `stream`refedefine a model member variable named `stream`

[DonAurelio]

For example, in one of the function signatures for a HIP event (below), the stream argument, from the model, is redefined by a template genared variable named stream.

void btx_push_message_lttng_ust_hip_hipStreamCreate_entry(
    void *
        btx_handle, int64_t vpid, uint64_t vtid, uint64_t stream) {

  common_data_t *common_data = (common_data_t *)btx_handle;

  bt_stream *stream = bt_trace_borrow_stream_by_index(
      common_data->downstream_trace, 0);

Possible solution: Rename template generated variables to btx_stream.

[TApplencourt]

Thanks for the fix!