[llvm] [CHERI] Define CHERI capability address space in computeRISCVDataLayout (PR #190806)

[Owen Anderson via llvm-commits]

resistor wrote:

@jrtc27 @arichardson can you confirm if you want to have these big CHERI purecap ABI names in upstream? I can limit this to just the cheriot otherwise.

https://github.com/llvm/llvm-project/pull/190806