powerpc/prom: move the device tree if not in declared memory.

If the device tree doesn't reside in the memory which is declared
inside it, it has to be moved as well as this memory will not be
mapped by the kernel.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/kernel/prom.c

@@ -124,8 +124,8 @@ static void __init move_device_tree(void)
 	size = fdt_totalsize(initial_boot_params);
 
 	if ((memory_limit && (start + size) > PHYSICAL_START + memory_limit) ||
-			overlaps_crashkernel(start, size) ||
-			overlaps_initrd(start, size)) {
+	    !memblock_is_memory(start + size - 1) ||
+	    overlaps_crashkernel(start, size) || overlaps_initrd(start, size)) {
 		p = __va(memblock_phys_alloc(size, PAGE_SIZE));
 		memcpy(p, initial_boot_params, size);
 		initial_boot_params = p;