prepare to remove /proc/sys/vm/hugepages_treat_as_movable

Now hugepages are definitely movable. So allocating hugepages from
ZONE_MOVABLE is natural and we have no reason to keep this parameter.
In order to allow userspace to prepare for the removal, let's leave
this sysctl handler as noop for a while.

ChangeLog v2:
 - shift to noop function instead of completely removing the parameter
 - rename patch title

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
enable MCG_SER

only for testing.