selftests: mlxsw: Add Bloom filter complex test

Bloom filter index computation is based on the values of
{rule & mask, mask ID, region ID} and the computation also varies
according to the region key size.

Add a test that exercises the possible combinations by creating
multiple chains using different key sizes and then pass a frame that
is supposed to to produce a hit on all of the regions.

Signed-off-by: Nir Dotan <nird@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>