ixgbe: fix_features rxvlan is independent of DCB and needs to be set

DCB can be used independent of if RX VLAN stripping is enabled
or disabled so remove erroneous check.

Also enable or disable VLAN stripping when features are applied so
hardware and feature flags are in sync.

CC: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Tested-by: Marcus Dennis <marcusx.e.dennis@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>