i40evf: enable support for VF VLAN tag stripping control

A recent commit 809481484e5d ("i40e/i40evf: support for VF VLAN tag
stripping control") added support for VFs to negotiate the control of
VLAN tag stripping. This should have allowed VFs to disable the feature.
Unfortunately, the flag was set only in netdev->feature flags and not in
netdev->hw_features.

This ultimately causes the stack to assume that it cannot change the
flag, so it was unchangeable and marked as [fixed] in the ethtool -k
output.

Fix this by setting the feature in hw_features first, just as we do for
the PF code. This enables ethtool -K to disable the feature correctly,
and fully enables user control of the VLAN tag stripping feature.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>