Add DPDK definition to DOXYGEN
Add DPDK definition to DOXYGEN

Change-Id: I04e8663b49b5f706940b7aada0a7c2cae913a82b
Signed-off-by: Keith Burns (alagalah) <469d26a9115c63bc10d4323e29088530ee1e798d@gmail.com>

vpp-dev/vpp,milanlenco/vpp,FDio/vpp,chrisy/vpp,vpp-dev/vpp,chrisy/vpp,vpp-dev/vpp,milanlenco/vpp,chrisy/vpp,GabrielGanne/vpp-flowtable,chrisy/vpp,GabrielGanne/vpp-flowtable,FDio/vpp,vpp-dev/vpp,vpp-dev/vpp,FDio/vpp,GabrielGanne/vpp-flowtable,chrisy/vpp,vpp-dev/vpp,vpp-dev/vpp,milanlenco/vpp,FDio/vpp,GabrielGanne/vpp-flowtable,FDio/vpp,FDio/vpp,chrisy/vpp,GabrielGanne/vpp-flowtable,milanlenco/vpp,chrisy/vpp,FDio/vpp,milanlenco/vpp,GabrielGanne/vpp-flowtable,milanlenco/vpp,chrisy/vpp,FDio/vpp