dpdk: New module with some code from netdev-dpdk.

There's a lot of code in netdev-dpdk which is not at all related to the
netdev interface, mostly the library initialization code.

This commit moves it to a new 'dpdk' module, to simplify 'netdev-dpdk'.

Also a new module 'dpdk-stub' is introduced to implement some functions
when DPDK is not available.  This replaces the old 'netdev-nodpdk'
module.

Some redundant includes are removed or reorganized as a consequence.

No functional change.

CC: Aaron Conole <aconole@redhat.com>
Signed-off-by: Daniele Di Proietto <diproiettod@vmware.com>
Acked-by: Aaron Conole <aconole@redhat.com>
Tested-by: Aaron Conole <aconole@redhat.com>

lib/dpdk.h

@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2016 Nicira, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef DPDK_H
+#define DPDK_H
+
+#ifdef DPDK_NETDEV
+
+#include <rte_config.h>
+#include <rte_lcore.h>
+
+#define NON_PMD_CORE_ID LCORE_ID_ANY
+
+#else
+
+#define NON_PMD_CORE_ID UINT32_MAX
+
+#endif /* DPDK_NETDEV */
+
+struct smap;
+
+void dpdk_init(const struct smap *ovs_other_config);
+void dpdk_set_lcore_id(unsigned cpu);
+const char *dpdk_get_vhost_sock_dir(void);
+
+#endif /* dpdk.h */