m68k/mm: remove dummy __swp definitions for nommu

The definitions are not required, let's remove them.

Link: https://lkml.kernel.org/r/20230113171026.582290-10-david@redhat.com


Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>