scsi: ufs: Handle runtime PM during hibernation

In hibernation path, if runtime suspend is triggered, the
freeze-thaw-restore callflow will be disrupted due to PM
runtime worker threads that get invoked which tries to
resume scsi host before resuming ufshc. Disbale runtime PM
at the beginning of freeze and enable it after restoring.
Apart from being executed after creating hibernation image,
Thaw is also a fallback mechanism in case of failed image
creation or restoration. So runtime PM can be enabled in
exit path of thaw.

Change-Id: I6afc8e556814c4bcf4482d79d03bd233f7c947d5
Signed-off-by: Anjana Hari <ahari@codeaurora.org>