[llvm] [RISCV] Increase GPRPair Allocation Priority (PR #159169)

[Sam Elliott via llvm-commits]

lenary wrote:

Looks to be achieved similarly with https://github.com/llvm/llvm-project/pull/160084 which also looks less disruptive and more general. Closing

https://github.com/llvm/llvm-project/pull/159169