IB/mlx5: Enlarge autogroup flow table

In order to enlarge the flow group size to 8k, we decrease
the number of flow group types to 6 and increase the flow
table size to 64k.

Flow group size is calculated as follow:
  group_size = table_size / (#group_types + 1)

Fixes: 038d2ef8 ('IB/mlx5: Add flow steering support')
Signed-off-by: Maor Gottlieb <maorg@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>