[llvm] [TableGen][DecoderEmitter] Add option to emit type-specialized `decodeToMCInst` (PR #146593)

[Rahul Joshi via llvm-commits]

jurahul wrote:

Looks like templating adds a little bit to the code size. Building the RISCVDisassembler.cpp.o in a release config with/without this change results in the following:

```
Old:
196112 ./build/lib/Target/RISCV/Disassembler/CMakeFiles/LLVMRISCVDisassembler.dir/RISCVDisassembler.cpp.o 
New:
196096 ./build/lib/Target/RISCV/Disassembler/CMakeFiles/LLVMRISCVDisassembler.dir/RISCVDisassembler.cpp.o
```

So, 16 bytes less. Not significant though.

https://github.com/llvm/llvm-project/pull/146593