m68knommu: mark all RAM as ZONE_DMA

There is no reason not to put all RAM in ZONE_DMA for these simple
m68k varients (same as the standard MMU m68k code does). With this
in place the usual dma_alloc_coherent() work as expected.

Signed-off-by: Greg Ungerer <[e-mail]>

arch/m68knommu/mm/init.c

···
 	{
 		unsigned long zones_size[MAX_NR_ZONES] = {0, };
 
-		zones_size[ZONE_DMA] = 0 >> PAGE_SHIFT;
-		zones_size[ZONE_NORMAL] = (end_mem - PAGE_OFFSET) >> PAGE_SHIFT;
-#ifdef CONFIG_HIGHMEM
-		zones_size[ZONE_HIGHMEM] = 0;
-#endif
+		zones_size[ZONE_DMA] = (end_mem - PAGE_OFFSET) >> PAGE_SHIFT;
 		free_area_init(zones_size);
 	}
 }