[llvm] [RISCV] Remove getOffsetOfLocalArea() (PR #93765)

[Pengcheng Wang via llvm-commits]

wangpc-pp wrote:

> If it exists I feel like we really should be including it, even if it is 0 in practice?

Just a rough scan, only X86 has different `LocalAreaOffset`.

https://github.com/llvm/llvm-project/pull/93765