Documentation/llvm: update IRC location

This should have been done with commit 91ed3ed0 ("MAINTAINERS: update
ClangBuiltLinux IRC chat") but I did not realize it was in two separate
spots.

Link: https://lkml.kernel.org/r/20210825211823.6406-3-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

@@ -114,7 +114,7 @@ Getting Help
 - `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
+- IRC: #clangbuiltlinux on irc.libera.chat
 - `Telegram <https://t.me/ClangBuiltLinux>`_: @ClangBuiltLinux
 - `Wiki <https://github.com/ClangBuiltLinux/linux/wiki>`_
 - `Beginner Bugs <https://github.com/ClangBuiltLinux/linux/issues?q=is%3Aopen+is%3Aissue+label%3A%22good+first+issue%22>`_