[llvm] [RISCV] Run DeadMachineInstructionElim after regalloc (PR #90598)

[Craig Topper via llvm-commits]

topperc wrote:

Are there any post-RA or even post-SSA uses of this pass on any other target? All I found were uses still in SSA form.

https://github.com/llvm/llvm-project/pull/90598