mm, memory_hotplug: remove obsolete generic_free_nodedata()

Commit 390511e1476e ("mm, memory_hotplug: drop arch_free_nodedata") drops
the last caller of generic_free_nodedata(). Remove it too.

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Miaohe Lin <[e-mail]>
Reviewed-by: David Hildenbrand <[e-mail]>
Reviewed-by: Anshuman Khandual <[e-mail]>
Reviewed-by: Oscar Salvador <[e-mail]>
Cc: Matthew Wilcox <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

include/linux/memory_hotplug.h

···
 ({								\
 	memblock_alloc(sizeof(*pgdat), SMP_CACHE_BYTES);	\
 })
-/*
- * This definition is just for error path in node hotadd.
- * For node hotremove, we have to replace this.
- */
-#define generic_free_nodedata(pgdat)	kfree(pgdat)
 
 extern pg_data_t *node_data[];
 static inline void arch_refresh_nodedata(int nid, pg_data_t *pgdat)
···
 {
 	BUG();
 	return NULL;
-}
-static inline void generic_free_nodedata(pg_data_t *pgdat)
-{
 }
 static inline void arch_refresh_nodedata(int nid, pg_data_t *pgdat)
 {