net/mlx5: fix shared flow counter lookup

net/mlx5: fix shared flow counter lookup

Currently, the shared counter search uses the wrong nested index which
is used by the pool index. The incorrect nested index using causes the
search go to incorrect counter pool is not existed.

Add the counter index to fix the incorrect nested use case.

Fixes: 4001d7ad26d4 ("net/mlx5: change Direct Verbs counter to indexed")

Signed-off-by: Suanming Mou <suanmingm@mellanox.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
Acked-by: Matan Azrad <matan@mellanox.com>