memory-hotplug-remove-memmap-of-sparse-vmemmap-fix

memory-hotplug-remove-memmap-of-sparse-vmemmap-fix

Defconfig for x86_64 complains:
arch/x86/mm/init_64.c: In function `vmemmap_free':
arch/x86/mm/init_64.c:1317: error: implicit declaration of function `remove_pagetable'

vmemmap_free is only used for CONFIG_MEMORY_HOTPLUG so let's move it
inside ifdef

Signed-off-by: Michal Hocko <mhocko@suse.cz>
Tested-by: Lin Feng <linfeng@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>