Remove libc-do-syscall from sysdep-dl-routines added by:
commit 3b33d6ed60
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date: Sun Jan 8 11:38:23 2017 -0200
Rework -fno-omit-frame-pointer support on i386
and use auto-generated io/rtld-libc-do-syscall.os instead. This fixes
BZ #28936.