From: Eric Dumazet <edumazet@google.com>
Date: Sat, 7 Dec 2024 16:22:48 +0000
I chose to remove this field in a separate patch to ease
potential bisection, in case one ndo_fdb_dump() is still
using the old way (cb->args[2] instead of ctx->fdb_idx)
Signed-off-by: Eric Dumazet <edumazet@google.com>