noDuffDevice was for Plan 9, but Plan 9 doesn't need it anymore.
It was also being set in s390x, mips, mipsle, and wasm, but
on those systems it had no effect since the SSA rules for those
architectures don't refer to it at all.
Change-Id: Ib85c0832674c714f3ad5091f0a022eb7cd3ebcdf
Reviewed-on: https://go-review.googlesource.com/c/go/+/655878
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Keith Randall <khr@google.com> Reviewed-by: Keith Randall <khr@golang.org>
Auto-Submit: Russ Cox <rsc@golang.org>