cmd/internal/objabi, cmd/link/internal: add new relocations used in internal linking

cmd/internal/objabi, cmd/link/internal: add new relocations used in internal linking

Change-Id: I1b7c258f0ea3b847a92ccd6644b653e11e7a5ef0
Reviewed-on: https://go-review.googlesource.com/c/go/+/555115
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: abner chenc <chenguoqi@loongson.cn>
Reviewed-by: Qiqi Huang <huangqiqi@loongson.cn>
Reviewed-by: sophie zhao <zhaoxiaolin@loongson.cn>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-by: David Chase <drchase@google.com>