vmxnet3: Enable HW Rx VLAN stripping by default

Make hw vlan tag stripping as enabled by default. Thereby remove
the code to conditionally enable it later.

Signed-off-by: Guolin Yang <gyang@vmware.com>
Signed-off-by: Shreyas N Bhatewara <sbhatewara@vmware.com>
Signed-off-by: David S. Miller <davem@davemloft.net>