dpdk: be a plugin

Change-Id: I238258cdeb77035adc5e88903d824593d0a1da90
Signed-off-by: Damjan Marion <damarion@cisco.com>
diff --git a/src/vnet/pg/stream.c b/src/vnet/pg/stream.c
index c46875e..560c4b0 100644
--- a/src/vnet/pg/stream.c
+++ b/src/vnet/pg/stream.c
@@ -442,9 +442,8 @@
     pg_buffer_index_t *bi;
     int n;
 
-#if DPDK > 0
-    s->buffer_bytes = VLIB_BUFFER_DATA_SIZE;
-#endif
+    if (vm->buffer_main->extern_buffer_mgmt)
+      s->buffer_bytes = VLIB_BUFFER_DATA_SIZE;
 
     if (!s->buffer_bytes)
       s->buffer_bytes = s->max_packet_bytes;