The driver no longer collects over SNMP. SNMP_HEALTH_PROFILE states
where the switch publishes uptime (TimeTicks), CPU and memory (tables
with one row per stack unit, first row as before); the application
polls and computes (napalm-device-types docs/STRUCTURE.md).
Interface counters now come from the 64-bit ifXTable where the switch
has it, as the application reads them for every device.
