mlxsw: Add operations structure for bloom filter calculation

Spectrum-4 will calculate hash function for bloom filter differently from
the existing ASICs.

There are two changes:
1. Instead of using one hash function to calculate 16 bits output (CRC-16),
   two functions will be used.
2. The chunks will be built differently, without padding.

As preparation for support of Spectrum-4 bloom filter, add 'ops'
structure to allow handling different calculation for different ASICs.

Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>