seccomp: Add missing compat_ioctl for notify

seccomp: Add missing compat_ioctl for notify

commit 3db81afd99494a33f1c3839103f0429c8f30cb9d upstream.

Executing the seccomp_bpf testsuite under a 64-bit kernel with 32-bit
userland (both s390 and x86) doesn't work because there's no compat_ioctl
handler defined. Add the handler.

Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Fixes: 6a21cc50f0c7 ("seccomp: add a return code to trap to userspace")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200310123332.42255-1-svens@linux.ibm.com
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>