s390/compat: fix compat wrappers for process_vm system calls

commit 82aabdb6f1eb61e0034ec23901480f5dd23db7c4 upstream.

The compat wrappers incorrectly called the non compat versions of
the system process_vm system calls.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>