octeontx2-af: Add SDP interface support

Added support for packet IO via SDK links which is used when
Octeon is connected as a end-point. Traffic host to end-point
and vice versa flow through SDP links. This patch also support
dual SDP blocks supported in 98xx silicon.

Signed-off-by: Radha Mohan Chintakuntla <radhac@marvell.com>
Signed-off-by: Nalla Pradeep <pnalla@marvell.com>
Signed-off-by: Subrahmanyam Nilla <snilla@marvell.com>
Signed-off-by: Sunil Goutham <sgoutham@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>