net/mlx5: fix memory leak on context allocation failure

net/mlx5: fix memory leak on context allocation failure

In shared device context creation, there is a missing validation when
one of the btree memory allocation fails that will cause a memory leak.

This adds a proper check to clean resources in case of failure.

Fixes: 632f0f19056f ("net/mlx5: manage shared counters in three-level table")
Cc: stable@dpdk.org
Signed-off-by: Michael Baum <michaelba@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>