cmd/link: handle SRODATALRELRO in xcoffUpdateOuterSize
This is a followup to CL 723580. This fixes cgo builds on AIX.
For #76038
Change-Id: Idea959615891f3f6e33932fae7a9043778db3366
Reviewed-on: https://go-review.googlesource.com/c/go/+/738920
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Dmitri Shuralyov <dmitshur@google.com> Reviewed-by: Cherry Mui <cherryyz@google.com>
Auto-Submit: Ian Lance Taylor <iant@golang.org>