Fix build error for numa_clear_node() under IA64

numa_clear_node() function is not implemented under IA64,
it will be called in unmap_cpu_on_node() in mm/memory_hotplug.c.
This cause build error under IA64, this patch adds numa_clear_node()
in IA64 to fix this problem.

[Added __cpuinit notation to numa_clear_node() to keep linker happy -Tony]

Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
diff --git a/arch/ia64/mm/numa.c b/arch/ia64/mm/numa.c
index 3efea7d..def782e 100644
--- a/arch/ia64/mm/numa.c
+++ b/arch/ia64/mm/numa.c
@@ -73,6 +73,11 @@
 	return -1;
 }
 
+void __cpuinit numa_clear_node(int cpu)
+{
+	unmap_cpu_from_node(cpu, NUMA_NO_NODE);
+}
+
 #ifdef CONFIG_MEMORY_HOTPLUG
 /*
  *  SRAT information is stored in node_memblk[], then we can use SRAT