[llvm] [RISCV] Cost UDIV/UREM by a constant power of 2 as a SHL/AND in getArithmeticInstrCost() (PR #179570)

[Simon Pilgrim via llvm-commits]

https://github.com/RKSimon requested changes to this pull request.

remove irrelevant x86 format fix

https://github.com/llvm/llvm-project/pull/179570