mm: remove obsolete alloc_migrate_target()

There's only declaration left in the header file. Remove it.

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Miaohe Lin <[e-mail]>
Reviewed-by: David Hildenbrand <[e-mail]>
Cc: Johannes Weiner <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

include/linux/page-isolation.h

···
 
 int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn,
 			int isol_flags);
-
-struct page *alloc_migrate_target(struct page *page, unsigned long private);
-
 #endif