Power: add an API to log wakeup reasons

Add API log_wakeup_reason() and expose it to userspace via sysfs path
/sys/kernel/wakeup_reasons/last_resume_reason

Change-Id: I81addaf420f1338255c5d0638b0d244a99d777d1
Signed-off-by: Ruchi Kandoi <kandoiruchi@google.com>
POWER: fix compile warnings in log_wakeup_reason

Change I81addaf420f1338255c5d0638b0d244a99d777d1 introduced compile
warnings, fix these.

Change-Id: I05482a5335599ab96c0a088a7d175c8d4cf1cf69
Signed-off-by: Ruchi Kandoi <kandoiruchi@google.com>
Power: Changes the permission to read only for sysfs file
/sys/kernel/wakeup_reasons/last_resume_reason

Change-Id: If25e8e416ee9726996518b58b6551a61dc1591e3
Signed-off-by: Ruchi Kandoi <kandoiruchi@google.com>
prctl: adds PR_SET_TIMERSLACK_PID for setting timer slack of an arbitrary thread.

Second argument is similar to PR_SET_TIMERSLACK, if non-zero then the
slack is set to that value otherwise sets it to the default for the thread.

Takes PID of the thread as the third argument.

This allows power/performance management software to set timer slack for
other threads according to its policy for the thread (such as when the
thread is designated foreground vs. background activity)

Change-Id: I744d451ff4e60dae69f38f53948ff36c51c14a3f
Signed-off-by: Ruchi Kandoi <kandoiruchi@google.com>

Conflicts:
	include/linux/prctl.h
	kernel/sys.c
tuna: defconfig: enable memory resource controller for cgroups
Power: Add an API call to log wakeup reasons