mm: treat indirectly reclaimable memory as free in overcommit logic

Indirectly reclaimable memory can consume a significant part of total
memory and it's actually reclaimable (it will be released under actual
memory pressure).This patch considers it as free in overcommit logic.

This patch is referenced from commit d79f7aa496fc ("mm: treat indirectly
reclaimable memory as free in overcommit logic") on upstream, as node
based vmstat global_node_page_state is not present zone based vmstat
global_page_state is used instead.

Change-Id: I9af71c566c83e24cd12e7653782b1898ccc7d680
Signed-off-by: Vijayanand Jitta <vjitta@codeaurora.org>