[llvm] [MC][Mips] Rename MipsMCAsmInfo to MipsELFMCAsmInfo (PR #112592)

[Hervé Poussineau via llvm-commits]

hpoussin wrote:

> There is a failure on Windows. Can you have a look at it? LLVM :: CodeGen/Mips/no-odd-spreg.ll

Fixed. It seems Windows hosts default to COFF output while Linux hosts default to ELF.
However, this test assumed ELF output without requesting it, and this PR starts to react on chosen output format.

https://github.com/llvm/llvm-project/pull/112592