net/mlx5: Check device capability for maximum flow counters

Added check for the maximal number of flow counters attached
to rule (FTE).

Fixes: bd5251db

 ('net/mlx5_core: Introduce flow steering destination of type counter')
Signed-off-by: Raed Salem <raeds@mellanox.com>
Reviewed-by: Maor Gottlieb <maorg@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>