[COMMON] soc: samsung: Introduce exynos cpu hotplug

[COMMON] soc: samsung: Introduce exynos cpu hotplug

exynos CPU hotplug driver supports the interface to enable or
disable cpu. All exynos drivers which want to hotplug cpu must
call the function CPU hotplug driver supported function.

CPU hotplug driver refers pm_qos class value of PM_QOS_CPU_ONLINE_MIN
and PM_QOS_CPU_ONLINE_MAX. Driver enables the cpu as mush as the
PM_QOS_CPU_ONLINE_MIN value unless this value is not bigger than
PM_QOS_CPU_ONLINE_MAX value. PM_QOS_CPU_ONLINE_MAX class has higher
priority.

Change-Id: I8b28b5198ec7e90a68579b1459d933dc35c673fc
Signed-off-by: Park Bumgyu <bumgyu.park@samsung.com>
Signed-off-by: Youngtae Lee <yt0729.lee@samsung.com>
Signed-off-by: Soohyun Kim <soohyuni.kim@samsung.com>