[RISCV] Use FMV.D for moving GPRPairs on RV32_Zdinx#169556

lenary merged 2 commits intollvm:mainllvm/llvm-project:mainfrom

lenary:pr/riscv-fmv-d-gprpairlenary/llvm-project:pr/riscv-fmv-d-gprpairCopy head branch name to clipboard