The following commit break vm2vm hard mode test cases:
commit db4014f2b65cb31bf ("use factorized default Rx/Tx configuration")
Investigation show that it needs enabling vlan offload since it is turn off
by default in some drivers, and Tx need it, especially when vm2vm is in hard mode.
Signed-off-by: Changchun Ouyang <changchun.ouyang@intel.com>
Tested-by: Jingguo Fu <jingguox.fu@intel.com>