soc: qcom: subsystem_sleep_stats: Add support soc sleep info

This change enhances subsystem_sleep_stats driver to give soc sleep
information including aosd, cxsd, ddr and ddr_stats.

Change-Id: I7be161158d5dc9b5d06a940cc69cf883d73fd803
Signed-off-by: Minghao Zhang <minghao@codeaurora.org>