devlink: Add documentation for OcteonTx2 AF

Add documentation for the following devlink params
- npc_mcam_high_zone_percent
- npc_def_rule_cntr
- nix_maxlf

Signed-off-by: Linu Cherian <lcherian@marvell.com>
Link: https://patch.msgid.link/20241105125620.2114301-4-lcherian@marvell.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>