ethernet: put vlib_get_buffers together
ethernet: put vlib_get_buffers together

The patch brings 0.8 clocks saved per pkt in IPv4 l3fwd case on Skylake.

Type: improvement

Signed-off-by: Zhiyong Yang <fbdb847fac8e5e50b588eb93d9ff9fd811b7568c@intel.com>
Change-Id: Ia8d3a27773bf959433380d7c219602b1e4a8e5bd

FDio/vpp,chrisy/vpp,FDio/vpp,chrisy/vpp,FDio/vpp,chrisy/vpp,chrisy/vpp,FDio/vpp,chrisy/vpp,FDio/vpp,FDio/vpp,FDio/vpp,chrisy/vpp,chrisy/vpp,chrisy/vpp,FDio/vpp