[PATCH 5/5] samples/bpf: fix hbm build error

[Matteo Croce <mcroce@redhat.com>]

Fix the following build error by declaring bpf_spin_lock in hbm.c.
Including the UAPI header generates tons of redefined symbol errors,
and including it in hbm.h breaks hbm_out_kern.c.

make -C samples/bpf/../../tools/lib/bpf/ RM='rm -rf' LDFLAGS= srctree=samples/bpf/../../ O=
  HOSTCC  samples/bpf/hbm.o
In file included from samples/bpf/hbm.c:49:
samples/bpf/hbm.h:12:23: error: field ‘lock’ has incomplete type
   12 |  struct bpf_spin_lock lock;
      |                       ^~~~
make[2]: *** [scripts/Makefile.host:109: samples/bpf/hbm.o] Error 1
make[1]: *** [Makefile:1763: samples/bpf/] Error 2

Signed-off-by: Matteo Croce <mcroce@redhat.com>
---
 samples/bpf/hbm.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/samples/bpf/hbm.c b/samples/bpf/hbm.c
index a79828ab273f..ca8e567b63c3 100644
--- a/samples/bpf/hbm.c
+++ b/samples/bpf/hbm.c
@@ -40,17 +40,22 @@
 #include <fcntl.h>
 #include <linux/unistd.h>
 
-#include <linux/bpf.h>
 #include <bpf/bpf.h>
+#include <linux/bpf.h>
 
 #include "bpf_load.h"
 #include "bpf_rlimit.h"
 #include "cgroup_helpers.h"
-#include "hbm.h"
 #include "bpf_util.h"
 #include "bpf/bpf.h"
 #include "bpf/libbpf.h"
 
+struct bpf_spin_lock {
+	__u32	val;
+};
+
+#include "hbm.h"
+
 bool outFlag = true;
 int minRate = 1000;		/* cgroup rate limit in Mbps */
 int rate = 1000;		/* can grow if rate conserving is enabled */
-- 
2.21.0