[llvm] [RISCV] Don't fold a pcrel addi into ld/st instructions with multiple uses (PR #80240)

[Visoiu Mistrih Francis via llvm-commits]

francisvm wrote:

Got it, so it's the low 12 bits of the symbol in `aupic xN, %pcrel_hi(symbol)`.

https://github.com/llvm/llvm-project/pull/80240