mlxsw: switchx2: Move SwitchX-2 trap groups out of main enum

The number of Spectrum trap groups is not infinite, but two identifiers
are occupied by SwitchX-2 specific trap groups. Free these identifiers
by moving them out of the main enum.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>