Use common help functions to free reserved pages.
Signed-off-by: NJiang Liu <jiang.liu@huawei.com>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>