[PATCH bpf-next] selftests/bpf: fix compiler warning in BPF_KPROBE definition in loop6.c

[Andrii Nakryiko <andrii@kernel.org>]

Add missing return type to BPF_KPROBE definition. Without it, compiler
generates the following warning:

progs/loop6.c:68:12: warning: type specifier missing, defaults to 'int' [-Wimplicit-int]
BPF_KPROBE(trace_virtqueue_add_sgs, void *unused, struct scatterlist **sgs,
           ^
1 warning generated.

Fixes: 86a35af628e5 ("selftests/bpf: Add a verifier scale test with unknown bounded loop")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
 tools/testing/selftests/bpf/progs/loop6.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/bpf/progs/loop6.c b/tools/testing/selftests/bpf/progs/loop6.c
index 2a7141ac1656..38de0331e6b4 100644
--- a/tools/testing/selftests/bpf/progs/loop6.c
+++ b/tools/testing/selftests/bpf/progs/loop6.c
@@ -65,8 +65,8 @@ int config = 0;
 int result = 0;
 
 SEC("kprobe/virtqueue_add_sgs")
-BPF_KPROBE(trace_virtqueue_add_sgs, void *unused, struct scatterlist **sgs,
-	   unsigned int out_sgs, unsigned int in_sgs)
+int BPF_KPROBE(trace_virtqueue_add_sgs, void *unused, struct scatterlist **sgs,
+	       unsigned int out_sgs, unsigned int in_sgs)
 {
 	struct scatterlist *sgp = NULL;
 	__u64 length1 = 0, length2 = 0;
-- 
2.24.1