98kbd{,-io} and 98spkr all went out with PC98 subarch.  Remove stale Makefile
entries that remained.
Signed-off-by: NArthur Othieno <apgo@patchbomb.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NDmitry Torokhov <dtor@mail.ru>