dpdk: bump default DPDK version to 18.05

Change-Id: I739d3e6c25efe8d32b2f4a60557c644edfe958e0
Signed-off-by: Damjan Marion <damarion@cisco.com>
diff --git a/dpdk/Makefile b/dpdk/Makefile
index 778a982..f02a993 100644
--- a/dpdk/Makefile
+++ b/dpdk/Makefile
@@ -27,7 +27,7 @@
 
 B := $(DPDK_BUILD_DIR)
 I := $(DPDK_INSTALL_DIR)
-DPDK_VERSION ?= 18.02.2
+DPDK_VERSION ?= 18.05
 PKG_SUFFIX ?= vpp1
 DPDK_BASE_URL ?= http://fast.dpdk.org/rel
 DPDK_TARBALL := dpdk-$(DPDK_VERSION).tar.xz