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 <[email protected]>
Acked-by: Jesper Dangaard Brouer <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
diff --git a/samples/bpf/xdp_monitor_user.c b/samples/bpf/xdp_monitor_user.c
index 05ad3f5..bf09b51 100644
--- a/samples/bpf/xdp_monitor_user.c
+++ b/samples/bpf/xdp_monitor_user.c
@@ -26,7 +26,7 @@ static const char *__doc_err_only__=
 #include <net/if.h>
 #include <time.h>
 
-#include "libbpf.h"
+#include <bpf/bpf.h>
 #include "bpf_load.h"
 #include "bpf_util.h"