octeontx2-af: npc: cn20k: Index management

octeontx2-af: npc: cn20k: Index management

In CN20K silicon, the MCAM is divided vertically into two banks.
Each bank has a depth of 8192.

The MCAM is divided horizontally into 32 subbanks, with each subbank
having a depth of 256.

Each subbank can accommodate either x2 keys or x4 keys. x2 keys are
256 bits in size, and x4 keys are 512 bits in size.

    Bank1                   Bank0
    |-----------------------------|
    |               |             | subbank 31 { depth 256 }
    |               |             |
    |-----------------------------|
    |               |             | subbank 30
    |               |             |
    ------------------------------
    ...............................

    |-----------------------------|
    |               |             | subbank 0
    |               |             |
    ------------------------------|

This patch implements the following allocation schemes in NPC.
The allocation API accepts reference (ref), limit, contig, priority,
and count values. For example, specifying ref=100, limit=200,
contig=1, priority=LOW, and count=20 will allocate 20 contiguous
MCAM entries between entries 100 and 200.

1. Contiguous allocation with ref, limit, and priority.
2. Non-contiguous allocation with ref, limit, and priority.
3. Non-contiguous allocation without ref.
4. Contiguous allocation without ref.

Signed-off-by: Ratheesh Kannoth <rkannoth@marvell.com>
Link: https://patch.msgid.link/20260224080009.4147301-2-rkannoth@marvell.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>