net/mlx4_core: Check the correct limitation on VFs for HA mode

The limit of 63 is only for virtual functions while the actual enforcement
was for VFs plus physical functions, fix that.

Fixes: e57968a1 ('net/mlx4_core: Support the HA mode for SRIOV VFs too')
Signed-off-by: Moni Shoua <monis@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>