net/mlx5: Fix memory leak on flow table creation error flow

When we create the ft object we also init rhltable in ft->fgs_hash.
So in error flow before kfree of ft we need to destroy that rhltable.

Fixes: 693c6883

 ("net/mlx5: Add hash table for flow groups in flow table")
Signed-off-by: Roi Dayan <roid@nvidia.com>
Reviewed-by: Maor Dickman <maord@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>