mlxsw: spectrum_router: Add Spectrum-{2, 3} adjacency group size ranges

Spectrum-{2,3} support different adjacency group size ranges compared to
Spectrum-1. Add an array describing these ranges and change the common
code to use the array which was set during the per-ASIC initialization.

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>