cmd/compile/internal: add register ABI information for s390x

cmd/compile/internal: add register ABI information for s390x

Update #40724

Change-Id: If8f2574259560b097db29347b2aecb098acef863
Reviewed-on: https://go-review.googlesource.com/c/go/+/719462
Reviewed-by: Keith Randall <khr@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Vishwanatha HD <vishwanatha.hd@ibm.com>
Reviewed-by: Keith Randall <khr@google.com>