vmxnet3: fix VLAN filtering

vmxnet3: fix VLAN filtering

During an MTU change, the adapter is restarted.  If hardware VLAN offload
is in use, this existing filter table would also be cleared.  Instead,
setup the shadow table once during device initialization and just update
during restart.

vmxnet3_dev_vlan_offload_set(dev, mask) was incorrectly treating the
mask parameter as the bitmask for vlan_strip and vlan_filter, whereas
the mask indicates only what has changed - the values for
vlan_stripping and vlan_filter needs to be taken from dev_conf.rxmode.

Fixes: f003fc383487 ("vmxnet3: enable vlan filtering")

Signed-off-by: Charles (Chas) Williams <ciwillia@brocade.com>
Signed-off-by: Nachiketa Prachanda <nprachan@brocade.com>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Acked-by: Remy Horton <remy.horton@intel.com>