cmd/link: correct libc dynamic linker path

cmd/link: correct libc dynamic linker path

Ref: https://github.com/riscv-non-isa/riscv-elf-psabi-doc/issues/114

Fixes #77209

Change-Id: I8b575a95ad4e6a7e792514d7fcf9497599c1e404
Reviewed-on: https://go-review.googlesource.com/c/go/+/737180
Reviewed-by: Pengcheng Wang <wangpengcheng.pp@bytedance.com>
Reviewed-by: Quim Muntal <quimmuntal@gmail.com>
TryBot-Bypass: Meng Zhuo <mengzhuo1203@gmail.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Carlos Amedee <carlos@golang.org>