[llvm] [CodeGen, CHERI] Add capability types to MVT. (PR #156616)

[Jessica Clarke via llvm-commits]

jrtc27 wrote:

> Additional note: I've opted to omit the `cAny` tblgen wildcard type from this patch to keep it minimal. I expect to add it in a subsequent patch.

You mean cPTR?

https://github.com/llvm/llvm-project/pull/156616