dpif-netdev: Add DPDK netdev.

Following patch adds DPDK netdev-class to userspace datapath. Now
OVS can use DPDK port for IO by just configuring DPDK port and then
adding dpdk type port to userspace datapath.

Refer to INSTALL.DPDK doc for further info.

This is based a patch from Gerald Rogers.

Signed-off-by: Gerald Rogers <gerald.rogers@intel.com>
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Acked-by: Thomas Graf <tgraf@redhat.com>

lib/netdev.c

@@ -31,6 +31,7 @@
 #include "fatal-signal.h"
 #include "hash.h"
 #include "list.h"
+#include "netdev-dpdk.h"
 #include "netdev-provider.h"
 #include "netdev-vport.h"
 #include "ofpbuf.h"
@@ -124,6 +125,7 @@ netdev_initialize(void)
         netdev_register_provider(&netdev_tap_class);
         netdev_register_provider(&netdev_bsd_class);
 #endif
+        netdev_dpdk_register();
 
         ovsthread_once_done(&once);
     }