[clang] [Clang][attr] Add cfi_salt attribute (PR #141846)

[Aaron Ballman via cfe-commits]

AaronBallman wrote:

> @AaronBallman I know of no other CFI attribute requests. 

Excellent, glad to hear there's not some massive set of changes waiting in the wings.

> (But keep in mind that I'm not the CFI expert I play on TV.)

Sorry, but you touched it last, so you own it. I don't make the rules. ;-) (I kid, I kid)

https://github.com/llvm/llvm-project/pull/141846