cmd/6l, cmd/internal/ld, cmd/internal/obj: remove Xsym/Xadd from compiler's Reloc
They don't really make any sense on this side of the compiler/linker divide.
Some of the code touching these fields was the support for R_TLS when
thechar=='6' which turns out to be dead and so I just removed all of that.
Change-Id: I4e265613c4e7fcc30a965fffb7fd5f45017f06f3
Reviewed-on: https://go-review.googlesource.com/9107
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>