octeontx2-af: add mbox to return CPT_AF_FLT_INT info

CPT HW would trigger the CPT AF FLT interrupt when CPT engines
hits some uncorrectable errors and AF is the one which receives
the interrupt and recovers the engines.
This patch adds a mailbox for CPT VFs to request for CPT faulted
and recovered engines info.

Signed-off-by: Srujana Challa <schalla@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>