mm: use totalram_pages instead of num_physpages at runtime

The global variable num_physpages is scheduled to be removed, so use
totalram_pages instead of num_physpages at runtime.

Change-Id: I4dc536af143784161cc2272da34c6c69b74d027a
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: James Morris <jmorris@namei.org>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: Patrick McHardy <kaber@trash.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Git-commit: 0ed5fd138539940a493dc69359cb2f49de70ad89
Signed-off-by: Lime Yang <limey@codeaurora.org>