[mlx5] rte_flow_query returns -ENOTSUP when querying count from main lcore

[Dmitry Kozlyuk]

Hi Burkay,

I noticed that you don't zero-initialize all the fields,
e.g. rte_flow_attr::group is not set in your code
either as flow_attr = {0} or as flow.attr_group = 0.
If this is also the case when querying, then you might
call rte_flow_query() with (partially) uninitialized arguments
and get the weird results that you have described.
You must initialize the structs fully
both when creating the flow and when querying the counter.