[PATCH bpf-next] docs/bpf: Update btf test programe code

[Rong Tao <rtoax@xxxxxxxxxxx>]

From: Rong Tao <rongtao@xxxxxxxx>

commit c64779e24e88("selftests/bpf: Merge most of test_btf into
test_progs") rename selftests/bpf btf test from 'test_btf.c' to
'prog_tests/btf.c'.

Signed-off-by: Rong Tao <rongtao@xxxxxxxx>
---
 Documentation/bpf/btf.rst | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Documentation/bpf/btf.rst b/Documentation/bpf/btf.rst
index cf8722f96090..59ccd9bad1e0 100644
--- a/Documentation/bpf/btf.rst
+++ b/Documentation/bpf/btf.rst
@@ -1062,4 +1062,5 @@ format.::
 7. Testing
 ==========
 
-Kernel bpf selftest `test_btf.c` provides extensive set of BTF-related tests.
+Kernel bpf selftest `prog_tests/btf.c` provides extensive set of BTF-related
+tests.
-- 
2.38.1