The id values for VF stats were not being offset correctly.
And getting xstats for VF device only worked if VF device supported
it; it did not support the generic stats.
Fixes: dc7680e8597c ("net/netvsc: support integrated VF")
Cc: stable@dpdk.org
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
cc9271f9e7