cmd/link: support -fno-plt compiled gcc objects on ppc64le

cmd/link: support -fno-plt compiled gcc objects on ppc64le

This is the initial trivial implemenation. Further improvements can be
made for local calls.

A test is added, but the -fno-plt option is ignored by gcc if binutils
does not support inline plt relocations, so the test is effectively
skipped on such hosts.

Fixes #53345

Change-Id: Ibf31c26b1a8551c942b21019df8782c00b7a563e
Reviewed-on: https://go-review.googlesource.com/c/go/+/412714
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Run-TryBot: Paul Murphy <murp@ibm.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Jenny Rakoczy <jenny@golang.org>
Auto-Submit: Jenny Rakoczy <jenny@golang.org>
Run-TryBot: Jenny Rakoczy <jenny@golang.org>