sysvipc: Implement semop based on semtimedop

sysvipc: Implement semop based on semtimedop

Besides semop being a subset of semtimedop, new 32-bit architectures
on Linux are not expected to provide the syscall (only the 64-bit time
semtimedop).

Also, Linux 5.1 only wired-up semtimedop for the 64-bit architectures
that missed it (powerpc, s390, and sparc).  This simplifies the code
to support it.

Checked on x86_64-linux-gnu and i686-linux-gnu.

Reviewed-by: Florian Weimer <fweimer@redhat.com>