samples: bpf: refactor header include path

Currently, header inclusion in each file is inconsistent.
For example, "libbpf.h" header is included as multiple ways.

    #include "bpf/libbpf.h"
    #include "libbpf.h"

Due to commit b552d33c ("samples/bpf: fix include path
in Makefile"), $(srctree)/tools/lib/bpf/ path had been included
during build, path "bpf/" in header isn't necessary anymore.

This commit removes path "bpf/" in header inclusion.
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

samples/bpf/fds_example.c

@@ -14,7 +14,7 @@
 
 #include <bpf/bpf.h>
 
-#include "bpf/libbpf.h"
+#include "libbpf.h"
 #include "bpf_insn.h"
 #include "sock_example.h"
 

samples/bpf/hbm.c

@@ -50,8 +50,8 @@
 #include "cgroup_helpers.h"
 #include "hbm.h"
 #include "bpf_util.h"
-#include "bpf/bpf.h"
-#include "bpf/libbpf.h"
+#include "bpf.h"
+#include "libbpf.h"
 
 bool outFlag = true;
 int minRate = 1000;		/* cgroup rate limit in Mbps */

samples/bpf/ibumad_user.c

@@ -25,7 +25,7 @@
 
 #include "bpf_load.h"
 #include "bpf_util.h"
-#include "bpf/libbpf.h"
+#include "libbpf.h"
 
 static void dump_counts(int fd)
 {

samples/bpf/sockex1_user.c

@@ -3,7 +3,7 @@
 #include <assert.h>
 #include <linux/bpf.h>
 #include <bpf/bpf.h>
-#include "bpf/libbpf.h"
+#include "libbpf.h"
 #include "sock_example.h"
 #include <unistd.h>
 #include <arpa/inet.h>

samples/bpf/sockex2_user.c

@@ -3,7 +3,7 @@
 #include <assert.h>
 #include <linux/bpf.h>
 #include <bpf/bpf.h>
-#include "bpf/libbpf.h"
+#include "libbpf.h"
 #include "sock_example.h"
 #include <unistd.h>
 #include <arpa/inet.h>

samples/bpf/xdp1_user.c

@@ -18,8 +18,8 @@
 #include <net/if.h>
 
 #include "bpf_util.h"
-#include "bpf/bpf.h"
-#include "bpf/libbpf.h"
+#include "bpf.h"
+#include "libbpf.h"
 
 static int ifindex;
 static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;

samples/bpf/xdp_adjust_tail_user.c

@@ -18,8 +18,8 @@
 #include <netinet/ether.h>
 #include <unistd.h>
 #include <time.h>
-#include "bpf/bpf.h"
-#include "bpf/libbpf.h"
+#include "bpf.h"
+#include "libbpf.h"
 
 #define STATS_INTERVAL_S 2U
 

samples/bpf/xdp_fwd_user.c

@@ -24,7 +24,7 @@
 #include <fcntl.h>
 #include <libgen.h>
 
-#include "bpf/libbpf.h"
+#include "libbpf.h"
 #include <bpf/bpf.h>
 
 

samples/bpf/xdp_redirect_cpu_user.c

@@ -25,7 +25,7 @@ static const char *__doc__ =
 #define MAX_PROG 6
 
 #include <bpf/bpf.h>
-#include "bpf/libbpf.h"
+#include "libbpf.h"
 
 #include "bpf_util.h"
 

samples/bpf/xdp_redirect_map_user.c

@@ -24,7 +24,7 @@
 
 #include "bpf_util.h"
 #include <bpf/bpf.h>
-#include "bpf/libbpf.h"
+#include "libbpf.h"
 
 static int ifindex_in;
 static int ifindex_out;

samples/bpf/xdp_redirect_user.c

@@ -24,7 +24,7 @@
 
 #include "bpf_util.h"
 #include <bpf/bpf.h>
-#include "bpf/libbpf.h"
+#include "libbpf.h"
 
 static int ifindex_in;
 static int ifindex_out;

samples/bpf/xdp_router_ipv4_user.c

@@ -24,7 +24,7 @@
 #include <sys/ioctl.h>
 #include <sys/syscall.h>
 #include "bpf_util.h"
-#include "bpf/libbpf.h"
+#include "libbpf.h"
 #include <sys/resource.h>
 #include <libgen.h>
 

samples/bpf/xdp_rxq_info_user.c

@@ -22,8 +22,8 @@ static const char *__doc__ = " XDP RX-queue info extract example\n\n"
 #include <arpa/inet.h>
 #include <linux/if_link.h>
 
-#include "bpf/bpf.h"
-#include "bpf/libbpf.h"
+#include "bpf.h"
+#include "libbpf.h"
 #include "bpf_util.h"
 
 static int ifindex = -1;

samples/bpf/xdp_tx_iptunnel_user.c

@@ -17,7 +17,7 @@
 #include <netinet/ether.h>
 #include <unistd.h>
 #include <time.h>
-#include "bpf/libbpf.h"
+#include "libbpf.h"
 #include <bpf/bpf.h>
 #include "bpf_util.h"
 #include "xdp_tx_iptunnel_common.h"

samples/bpf/xdpsock_user.c

@@ -27,8 +27,8 @@
 #include <time.h>
 #include <unistd.h>
 
-#include "bpf/libbpf.h"
-#include "bpf/xsk.h"
+#include "libbpf.h"
+#include "xsk.h"
 #include <bpf/bpf.h>
 
 #ifndef SOL_XDP