include/linux/memory_hotplug.h: remove duplicate declaration of offline_pages()

offline_pages() is already declared in this file.

Just remove the duplicated one.

Link: http://lkml.kernel.org/r/20181205031357.24769-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/memory_hotplug.h

@@ -331,7 +331,6 @@ extern int arch_add_memory(int nid, u64 start, u64 size,
 		struct vmem_altmap *altmap, bool want_memblock);
 extern void move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn,
 		unsigned long nr_pages, struct vmem_altmap *altmap);
-extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages);
 extern bool is_memblock_offlined(struct memory_block *mem);
 extern int sparse_add_one_section(int nid, unsigned long start_pfn,
 				  struct vmem_altmap *altmap);