[clang] [llvm] [MIPS] Add FeatureMSA to i6400 and i6500 cores (PR #134985)

[Mallikarjuna Gouda via llvm-commits]

mgoudar wrote:

hi @brad0 I am seeing fails in https://lab.llvm.org/buildbot/#/builders/94 post this pr merge. 
test llvm/test/CodeGen/Mips/msa/arithmetic.ll fails with a crash. I am trying to reproduce at my side


https://github.com/llvm/llvm-project/pull/134985