[POWERPC] Add remove_memory() for 64-bit powerpc

Supply remove_memory() function for 64-bit powerpc.  This is still
not quite complete as it needs to do some more arch-specific stuff,
which will be added in a later patch.

Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/mm/mem.c

@@ -129,6 +129,22 @@ int __devinit arch_add_memory(int nid, u64 start, u64 size)
 	return __add_pages(zone, start_pfn, nr_pages);
 }
 
+#ifdef CONFIG_MEMORY_HOTREMOVE
+int remove_memory(u64 start, u64 size)
+{
+	unsigned long start_pfn, end_pfn;
+	int ret;
+
+	start_pfn = start >> PAGE_SHIFT;
+	end_pfn = start_pfn + (size >> PAGE_SHIFT);
+	ret = offline_pages(start_pfn, end_pfn, 120 * HZ);
+	if (ret)
+		goto out;
+	/* Arch-specific calls go here - next patch */
+out:
+	return ret;
+}
+#endif /* CONFIG_MEMORY_HOTREMOVE */
 #endif /* CONFIG_MEMORY_HOTPLUG */
 
 void show_mem(void)