In Spectrum-2, all the packets are time stamped, the MTPCPC register is
used to configure the types of packets that will adjust the correction
field and which port will trap PTP packets.

If ingress correction is set on a port for a given packet type, then
when such a packet is received via the port, the current time stamp is
subtracted from the correction field.

If egress correction is set on a port for a given packet type, then when
such a packet is transmitted via the port, the current time stamp is
added to the correction field.

Assuming the systems is configured correctly, the above means that the
correction field will contain the transient delay between the ports.

Add this register for a future use in order to support PTP in Spectrum-2.
Signed-off-by: Danielle Ratson <danieller@nvidia.com>
Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>