[dev.regabi] cmd/compile: remove unneeded indirection

Thanks to package reorganizing, we can remove types.TypeLinkSym by
simply having its only callers use reflectdata.TypeLinksym directly.

Passes toolstash -cmp.

Change-Id: I5bc5dbb6bf0664af43ae5130cfe1f19bd23b2bfe
Reviewed-on: https://go-review.googlesource.com/c/go/+/280644


Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>