net/mlx5: E-Switch, Use the correct free() function

We must use kvfree() for something that could have been allocated with vzalloc(),
do that.

Fixes: 5742df0f ('net/mlx5: E-Switch, Introduce VST vport ingress/egress ACLs')
Fixes: 86d722ad ('net/mlx5: Use flow steering infrastructure for mlx5_en')
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Reported-by: Ilya Lesokhin <ilyal@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>