[llvm] [RISCV] Fix inline asm error for block address (PR #66640)

[Wang Pengcheng via llvm-commits]

wangpc-pp wrote:

Optimizations will be done in my rework of [[RISCV] Teach RISCVMergeBaseOffset to handle inline asm](https://reviews.llvm.org/D158062).

https://github.com/llvm/llvm-project/pull/66640