Octeontx2-af: Fetch MAC channel info from firmware

Packet ingress and egress MAC/serdes channel numbers are configurable
on CN10K series of silicons. These channel numbers inturn used while
installing MCAM rules to match ingress/egress port. Fetch these channel
numbers from firmware at driver init time.

Signed-off-by: Hariprasad Kelam <hkelam@marvell.com>
Signed-off-by: Sunil Kovvuri Goutham <sgoutham@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>