[PATCH bpf-next v4] docs/bpf: Update btf selftests program and add link

[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>
---
v4: v3 -> v4
    s/bpf/BPF
v3: v2 -> v3
    s/Kernel bpf selftest/The kernel BPF selftest
    s/provides extensive/provides an extensive
    https://lore.kernel.org/lkml/tencent_C597352AB3AF24A35A88CC06A3421E590B08@xxxxxx/
v2: https://lore.kernel.org/lkml/tencent_114656E8259D0AEA2BDB6810E29241995006@xxxxxx/
v1: https://lore.kernel.org/lkml/tencent_7F84D04F96EBE594CAD5EBD12815A2B00106@xxxxxx/
---
 Documentation/bpf/btf.rst | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/Documentation/bpf/btf.rst b/Documentation/bpf/btf.rst
index cf8722f96090..7cd7c5415a99 100644
--- a/Documentation/bpf/btf.rst
+++ b/Documentation/bpf/btf.rst
@@ -1062,4 +1062,9 @@ format.::
 7. Testing
 ==========
 
-Kernel bpf selftest `test_btf.c` provides extensive set of BTF-related tests.
+The kernel BPF selftest `tools/testing/selftests/bpf/prog_tests/btf.c`_
+provides an extensive set of BTF-related tests.
+
+.. Links
+.. _tools/testing/selftests/bpf/prog_tests/btf.c:
+   https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/tools/testing/selftests/bpf/prog_tests/btf.c
-- 
2.38.1