devel/llvm-{cheri,morello}: Update to new snapshots

llvm-cheri:

• This updates from an LLVM 13 base to an LLVM 14 base.
• Save a little compile time by dropping MIPS support. The CHERI MIPS target still exists, but CheriBSD no longer supports it and the places that use it (e.g., https://cheri-compiler-explorer.cl.cam.ac.uk) use a Linux build.

llvm-morello:

• Minor optimization improvements