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: NYijing Wang <wangyijing@huawei.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

arch/ia64/include/asm/numa.h

@@ -67,14 +67,13 @@ extern int paddr_to_nid(unsigned long paddr);
 
 extern void map_cpu_to_node(int cpu, int nid);
 extern void unmap_cpu_from_node(int cpu, int nid);
-
+extern void numa_clear_node(int cpu);
 
 #else /* !CONFIG_NUMA */
 #define map_cpu_to_node(cpu, nid)	do{}while(0)
 #define unmap_cpu_from_node(cpu, nid)	do{}while(0)
-
 #define paddr_to_nid(addr)	0
-
+#define numa_clear_node(cpu)	do { } while (0)
 #endif /* CONFIG_NUMA */
 
 #endif /* _ASM_IA64_NUMA_H */

arch/ia64/mm/numa.c

@@ -73,6 +73,11 @@ int __meminit __early_pfn_to_nid(unsigned long pfn)
 	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