net/mlx5: synchronize flow counter pool creation

net/mlx5: synchronize flow counter pool creation

Currently, counter operations are not thread safe as the counter
pools' array resize is not protected.

This commit protects the container pools' array resize using a spinlock.
The original counter pool statistic memory allocate is moved to the
host thread in order to minimize the critical section. Since that pool
statistic memory is required only in query time. The container pools'
array should be resized by the user threads, the new pool may be used
by other rte_flow APIs before the host thread resize is done, if the
pool is not saved to the pools' array, the specified counter memory will
not be found as the pool is not saved to the counter management pool
array. The pool raw statistic memory will be filled in host thread.

The shared counters will be protected in other commit.

Signed-off-by: Suanming Mou <suanmingm@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>