DEDUP: a dedup module to control LKSM

DEDUP: a dedup module to control LKSM

To manage LKSM in the kernel, a dedup module is added to resourced codebase.

The resourced daemon checks memory pressure level when an event is delivered
from the kernel. When the memory pressure level is crossed the predefined
threshold (which is configured by memory.conf), the daemon requests to invoke
memory deduplication via sysfs interface.

In order to enable a dedup module in resourced, the kernel should support LKSM
features.

Change-Id: I6bec596d40e68e1d6cc0c047d80ef30700ab846e
Signed-off-by: Sung-hun Kim <sfoon.kim@samsung.com>