soc: qcom: glink_ssr: Add support for ss_info without notify edges

In probe function ss_info requires atleast one notify edge in order
to register for subsystem restart notification callback.

Add support for ss_info to register for subsystem restart notification
callback even if there is no edge to notify.

CRs-Fixed: 2223709
Change-Id: I7fdbce0c4836a18cfce9a30dae379183b3be9b1a
Signed-off-by: Dhoat Harpal <hdhoat@codeaurora.org>