[PATCH] x86_64: fix memory hotplug build with NUMA=n

This is to fix compile error of x86-64 memory hotplug without any NUMA
option.

  CC      arch/x86_64/mm/init.o
arch/x86_64/mm/init.c:501: error: redefinition of 'memory_add_physaddr_to_nid'
include/linux/memory_hotplug.h:71: error: previous definition of 'memory_add_phys
addr_to_nid' was here
arch/x86_64/mm/init.c:509: error: redefinition of 'memory_add_physaddr_to_nid'
arch/x86_64/mm/init.c:501: error: previous definition of 'memory_add_physaddr_to_
nid' was here

I confirmed compile completion with !NUMA, (NUMA & !ACPI_NUMA),
or (NUMA & ACPI_NUMA).
Signed-off-by: NYasunori Goto <y-goto@jp.fujitsu.com>
Acked-by: NAndi Kleen <ak@suse.de>
Cc: "Randy.Dunlap" <rdunlap@xenotime.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

arch/x86_64/mm/init.c

@@ -496,7 +496,7 @@ int remove_memory(u64 start, u64 size)
 }
 EXPORT_SYMBOL_GPL(remove_memory);
 
-#ifndef CONFIG_ACPI_NUMA
+#if !defined(CONFIG_ACPI_NUMA) && defined(CONFIG_NUMA)
 int memory_add_physaddr_to_nid(u64 start)
 {
 	return 0;
@@ -504,13 +504,6 @@ int memory_add_physaddr_to_nid(u64 start)
 EXPORT_SYMBOL_GPL(memory_add_physaddr_to_nid);
 #endif
 
-#ifndef CONFIG_ACPI_NUMA
-int memory_add_physaddr_to_nid(u64 start)
-{
-	return 0;
-}
-#endif
-
 #endif /* CONFIG_MEMORY_HOTPLUG */
 
 #ifdef CONFIG_MEMORY_HOTPLUG_RESERVE