Use rte_mempool private data for storing vlib_buffer_t

Change-Id: If3fc88a35bc0b736376113a39667caea42802ea1
Signed-off-by: Damjan Marion <damarion@cisco.com>
diff --git a/dpdk/Makefile b/dpdk/Makefile
index a07e861..dabbf6a 100644
--- a/dpdk/Makefile
+++ b/dpdk/Makefile
@@ -16,7 +16,7 @@
 
 DPDK_BUILD_DIR        ?= $(CURDIR)/_build
 DPDK_INSTALL_DIR      ?= $(CURDIR)/_install
-DPDK_PKTMBUF_HEADROOM ?= 256
+DPDK_PKTMBUF_HEADROOM ?= 128
 DPDK_DOWNLOAD_DIR     ?= $(HOME)/Downloads
 DPDK_MARCH            ?= native
 DPDK_DEBUG            ?= n