octeontx2-af: Add support to flush full CPT CTX cache

Adds support to flush or invalidate CPT CTX entries as part of FLR
and also provides a mailbox to flush CPT CTX entries in case of
graceful exit.
This patch also adds support for AF -> CPT PF uplink mailbox messages
and adds a new mbox message to submit a CPT instruction from AF.

Signed-off-by: Srujana Challa <schalla@marvell.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>