Add m68k seccomp definitions to seccomp_bpf self test code.

Tested on ARAnyM.
Signed-off-by: Michael Schmitz <schmitzmic@gmail.com>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/r/20230112035529.13521-4-schmitzmic@gmail.comSigned-off-by: Geert Uytterhoeven <geert@linux-m68k.org>