octeontx2-af: npc: cn20k: add debugfs support

octeontx2-af: npc: cn20k: add debugfs support

CN20K silicon divides the NPC MCAM into banks and subbanks, with each
subbank configurable for x2 or x4 key widths. This patch adds debugfs
entries to expose subbank usage details and their configured key type.

A debugfs entry is also added to display the default MCAM indexes
allocated for each pcifunc.

Additionally, debugfs support is introduced to show the mapping between
virtual indexes and real MCAM indexes, and vice versa.

Signed-off-by: Ratheesh Kannoth <rkannoth@marvell.com>
Link: https://patch.msgid.link/20260224080009.4147301-13-rkannoth@marvell.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>