ANDROID: PM: sleep: export device_pm_callback_start/end trace event

Export the device_pm_callback_start/end tracepoint so it can be used
in loadable modules.

Bug: 158528747

Change-Id: I31b99032b351d6a548f6c0ee4e02655aefae647f
Signed-off-by: Changki Kim <changki.kim@samsung.com>