net/octeontx2: support SDP interface

net/octeontx2: support SDP interface

System DPI Packet Interface Unit (SDP) is a co-processor
of OCTEON TX2 which provides PCIe endpoint support for a
remote host to DMA packets into and out of the OCTEON TX2 SoC.
SDP interface comes in to live only when it is connected in
EP mode. It exposes input and output queue pairs to remote host
for instruction input and packet output. It can be used as
a communication channel between remote host and OCTEON TX2.
Host machine needs to use corresponding user/kernel mode
driver to communicate with SDP interface on OCTEON TX2 SoC.

SDP interface support is limited to SDP PF device now.
No SDP VF support.

Signed-off-by: Subrahmanyam Nilla <snilla@marvell.com>
Signed-off-by: Venkateshwarlu Nalla <venkatn@marvell.com>
Acked-by: Jerin Jacob <jerinj@marvell.com>