Revert "tools include s390: Grab a copy of arch/s390/include/uapi/asm/unistd.h"

Revert "tools include s390: Grab a copy of arch/s390/include/uapi/asm/unistd.h"

This reverts commit f120c7b187e6c418238710b48723ce141f467543 which is no
longer required with the introduction of a syscall.tbl on s390.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Thomas Richter <tmricht@linux.vnet.ibm.com>
Cc: linux-s390@vger.kernel.org
LPU-Reference: 1518090470-2899-2-git-send-email-brueckner@linux.vnet.ibm.com
Link: https://lkml.kernel.org/n/tip-q1lg0nvhha1tk39ri9aqalcb@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>