soc: qcom: smem: Add support for suspend to disk

Add support to smem driver for suspend to disk feature.
SMEM is cleared during Hibernation. Initialize SMEM
during resume from Hibernation.

Change-Id: I6e9b912f5be46aa21923ce357cc9c0e7fa97c5a7
Signed-off-by: Rama Krishna Phani A <rphani@codeaurora.org>