Update git submodules

Update git submodules

* Update docs/submodules/samplevnf from branch 'master'
  - Merge "Add support for reception of jumbo frames"
  - Add support for reception of jumbo frames

    Jumbo frames are now supported through the addition of a "mtu"
    parameter of the port in the config file.
    Setting the mtu to a value higher than 1500 bytes will enable
    the reception of jumbo frames.
    In addition, the rte_eth_dev_set_mtu is now set for all pmds.
    Finally, setting mbuf_size does not set MEMPOOL_F_NO_SPREAD
    anymore. This option was only used for pure debugging.

    Big packets can be received using two ways
    - Using multiple "small" mbufs, i.e. around 2K. This is the default.
    - Using one big mbuf holding the whole packet. This can be enabled
      by setting a parameter mbuf_size in the receiving core configuration

    Change-Id: Idd60ad31f41c89f9522dff4d894af2696b7a2ea1
    Signed-off-by: Xavier Simonart <xavier.simonart@intel.com>