docs/bpf: Fix "file doesn't exist" warnings in {llvm_reloc,btf}.rst

scripts/documentation-file-ref-check reports warnings for (valid) cross-links
of form:

  :ref:`Documentation/bpf/btf <BTF_Ext_Section>`

Adding extension to the file name helps to avoid the warning, e.g:

  :ref:`Documentation/bpf/btf.rst <BTF_Ext_Section>`

Fixes: be4033d36070 ("docs/bpf: Add description for CO-RE relocations")
Reported-by: kernel test robot <[email protected]>
Signed-off-by: Eduard Zingerman <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Acked-by: Jiri Olsa <[email protected]>
Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]
Link: https://lore.kernel.org/bpf/[email protected]

0 files changed, 0 insertions, 0 deletions