ixgbevf: set vlan_features in a single write instead of several ORs

Clean up the setting of vlan_features by enabling all features at once.

Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>