samples: bpf: include bpf/bpf.h instead of local libbpf.h

There are two files in the tree called libbpf.h which is becoming
problematic.  Most samples don't actually need the local libbpf.h
they simply include it to get to bpf/bpf.h.  Include bpf/bpf.h
directly instead.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
diff --git a/samples/bpf/tracex5_user.c b/samples/bpf/tracex5_user.c
index 4e2774b..c4ab91c 100644
--- a/samples/bpf/tracex5_user.c
+++ b/samples/bpf/tracex5_user.c
@@ -5,7 +5,7 @@
 #include <linux/filter.h>
 #include <linux/seccomp.h>
 #include <sys/prctl.h>
-#include "libbpf.h"
+#include <bpf/bpf.h>
 #include "bpf_load.h"
 #include <sys/resource.h>