[llvm] [gitattributes] Mark some llvm-rc inputs as requiring LF newlines (PR #113222)

[Martin Storsjö via llvm-commits]

mstorsjo wrote:

The buildbots should have been refreshed now, and this solution with forcing the newlines for these specific files does work (I tested it in a separate checkout where `core.autocrlf` isn't set), so if you're ok with this, I'd prefer going this way.

https://github.com/llvm/llvm-project/pull/113222