net/mlx5: fix flow counters creation

net/mlx5: fix flow counters creation

The Flow counter creation function contains two problems:

  - Flow counter object in Verbs is not freed in case of memory
    allocation error. The call of counter Verbs object deallocating
    function is added to fix.

  - The initial value of reference counter is set to one in order
    to provide the correct counter object freeing in the
    flow_verbs_counter_release() function. The reference counter
    field should be initialized to one.

Fixes: 60bd8c9747e8 ("net/mlx5: add count flow action")
Cc: stable@dpdk.org
Signed-off-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>