[lld] [llvm] [llvm][RISCV] Enable trailing fences for seq-cst stores by default (PR #87376)

[Alex Bradbury via llvm-commits]

asb wrote:

Reverted due to the atomics ABI patch needing to be reverted https://github.com/llvm/llvm-project/pull/84597#issuecomment-2079128332 - see that PR for discussion.

https://github.com/llvm/llvm-project/pull/87376