net/mlx5: Enlarge the NIC TC offload table size

The NIC TC offload table size was hard coded to 1k. Change it to be

      min(max NIC RX table size,
	  min(max flow counters, 64k) * num flow groups)

where the max values are read from the firmware and the number of
flow groups is hard-coded as before this change.

We don't know upfront the division of flows to groups (== different masks).
This setup allows each group to be of size up to the where we want to go
(when supported, all offloaded flows use counters). Thus, we don't expect
multiple occurences for a group which in turn would add steering hops.

Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>