telemetry: fix using ports of different types

telemetry: fix using ports of different types

Different NIC ports can have different numbers of xstats on them, which
means that we can't just use the xstats list from the first port registered
in the telemetry library. Instead, we need to check the type of each port -
by checking its ops structure pointer - and register each port type once
with the metrics lib.

Fixes: fdbdb3f9ce46 ("telemetry: add initial connection socket")
Cc: stable@dpdk.org
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Kevin Laatz <kevin.laatz@intel.com>