net: dsa: netc: add support for the standardized counters

net: dsa: netc: add support for the standardized counters

Each user port of the NETC switch supports 802.3 basic and mandatory
managed objects statistic counters and IETF Management Information
Database (MIB) package (RFC2665) and Remote Network Monitoring (RMON)
counters. And all of these counters are 64-bit registers. In addition,
some user ports support preemption, so these ports have two MACs, MAC
0 is the express MAC (eMAC), MAC 1 is the preemptible MAC (pMAC). So
for ports that support preemption, the statistics are the sum of the
pMAC and eMAC statistics.

Note that the current switch driver does not support preemption, all
frames are sent and received via the eMAC by default. The statistics
read from the pMAC should be zero.

Signed-off-by: Wei Fang <wei.fang@nxp.com>
Link: https://patch.msgid.link/20260518082506.1318236-15-wei.fang@nxp.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>