Commit 214496cb ("ia64: make SPARSEMEM default and disable
DISCONTIGMEM") removed the last enabler of ARCH_DISCONTIGMEM_DEFAULT,
hence the memory model can no longer default to DISCONTIGMEM_MANUAL.

Link: https://lkml.kernel.org/r/20210312141208.3465520-1-geert@linux-m68k.orgSigned-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: NMike Rapoport <rppt@linux.ibm.com>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>