drivers/rtc/class: convert from Legacy pm ops to dev_pm_ops

Convert drivers/rtc/class to use dev_pm_ops for power management and
remove Legacy PM ops hooks.  With this change, rtc class registers
suspend/resume callbacks via class->pm (dev_pm_ops) instead of Legacy
class->suspend/resume.  When __device_suspend() runs call-backs, it will
find class->pm ops for the rtc class.

Signed-off-by: Shuah Khan <shuah.kh@samsung.com>
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Cc: Shuah Khan <shuahkhan@gmail.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>