[llvm] [MSP430] Compute c+1 at the operand bit width in EmitCMP (PR #195892)

[Sergei Barannikov via llvm-commits]

s-barannikov wrote:

FWIW you don't need to update commit message, GitHub ignores it and uses the PR description when merging.

https://github.com/llvm/llvm-project/pull/195892