powerpc: Use HAVE_MEMBLOCK_NODE_MAP

powerpc doesn't access early_node_map[] directly and enabling
HAVE_MEMBLOCK_NODE_MAP is trivial - replacing add_active_range() calls
with memblock_set_node() and selecting HAVE_MEMBLOCK_NODE_MAP is
enough.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Yinghai Lu <yinghai@kernel.org>
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 2dd6bdd..8e2eb66 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -199,7 +199,7 @@
 		unsigned long start_pfn, end_pfn;
 		start_pfn = memblock_region_memory_base_pfn(reg);
 		end_pfn = memblock_region_memory_end_pfn(reg);
-		add_active_range(0, start_pfn, end_pfn);
+		memblock_set_node(0, (phys_addr_t)ULLONG_MAX, 0);
 	}
 
 	/* Add all physical memory to the bootmem map, mark each area