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: Add an API call to log wake wakeup reason

Change-Id: I8bf670b07dcd52e29214ebb4e6e42dddd8c3d35e
Signed-off-by: Ruchi kandoi <kandoiruchi@google.com>
power: max17048: power down if the battery voltage is too low

The battery could be not charged depends on system load even
if the charger is plugged. Since application doesn't power
down the device when the charger is plugged even if battery
level reach to 0%. As a result, the battery could be severely
drained under this condition.
To avoid sudden power loss by UVLO, monitor the battery voltage
and power down the device if the battery voltage drop below the
threshold.

Change-Id: I88dd068bdfb5aa39c8c35511432bf5a10bc70db5
Signed-off-by: choongryeol.lee <choongryeol.lee@lge.com>

Conflicts:

	drivers/power/max17048_battery.c
arm/dt: hammerhead: set power down vbatt level to 3.05V

To prevent sudden power loss by UVLO, fuel gauge driver
monitors the battery voltage and power down the device
if battery voltage falls below 3.05V.

Change-Id: Id45acc12edcffe8cc534ebdde083c46ed6573f95
Signed-off-by: choongryeol.lee <choongryeol.lee@lge.com>