Documentation/llvm: update mailing list

We are now at llvm@lists.linux.dev.

Link: https://lkml.kernel.org/r/20210825211823.6406-2-nathan@kernel.orgSigned-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/kbuild/llvm.rst

@@ -111,7 +111,8 @@ Getting Help
 ------------
 
 - `Website <https://clangbuiltlinux.github.io/>`_
-- `Mailing List <https://groups.google.com/forum/#!forum/clang-built-linux>`_: <clang-built-linux@googlegroups.com>
+- `Mailing List <https://lore.kernel.org/llvm/>`_: <llvm@lists.linux.dev>
+- `Old Mailing List Archives <https://groups.google.com/g/clang-built-linux>`_
 - `Issue Tracker <https://github.com/ClangBuiltLinux/linux/issues>`_
 - IRC: #clangbuiltlinux on chat.freenode.net
 - `Telegram <https://t.me/ClangBuiltLinux>`_: @ClangBuiltLinux