[llvm] [NFC][MC][Lanai] Rearrange decoder functions for Lanai disassembler (PR #154993)

[Sergei Barannikov via llvm-commits]

s-barannikov wrote:

Can't comment inline for some reason.
Will the diff be smaller without clang-format on/off changes?


https://github.com/llvm/llvm-project/pull/154993