sch_dsmark: improve memory locality

Memory placement in sch_dsmark is silly : Better place mask/value
in the same cache line.

Also, we can embed small arrays in the first cache line and
remove a potential cache miss.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>