[Driver] Make ELF -nopie specific to OpenBSD (#72578)

-no-pie[1]/-nopie is rarely used and among the rare uses almost
everwhere uses -no-pie, since GCC does not recognize -nopie.
However, OpenBSD seems to use -nopie. Therefore, make -nopie specific
to OpenBSD to prevent newer ToolChains (Solaris, SerenityOS) from cargo
culting and copying -nopie.

[1]: https://reviews.llvm.org/D35462