[llvm] [CodeGen] Fix InstructionCount remarks for MI bundles (PR #107621)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> > This is probably by design. Code is supposed to logically treat a bundle as one instruction
> 
> Some targets use bundles to mark instruction packet boundaries, no? IMO, that shouldn't be counted as one instruction.

Yes, that was the original use (assuming some details about how packets are represented). I don't know what "InstructionCount" here is supposed to really mean though

https://github.com/llvm/llvm-project/pull/107621