mlxsw: reg: Move all trap groups under the same enum

After the previous patch the split is no longer necessary and all the
trap groups can be moved under the same 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>