octeontx2-pf: CN20K mbox REQ/ACK implementation for NIC PF

octeontx2-pf: CN20K mbox REQ/ACK implementation for NIC PF

This implementation uses separate trigger interrupts for request,
response messages against using trigger message data in CN10K.
This patch adds support for basic mbox implementation for CN20K
from NIC PF side.

Signed-off-by: Sai Krishna <saikrishnag@marvell.com>
Signed-off-by: Sunil Kovvuri Goutham <sgoutham@marvell.com>
Signed-off-by: Subbaraya Sundeep <sbhatta@marvell.com>
Link: https://patch.msgid.link/1749639716-13868-5-git-send-email-sbhatta@marvell.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>