drivers:soc: Avoid use of uninitialized variable

While notifier de_register, we access the list which is not initialized.
Hence can result in access of uninitialized variable.
Update the loop to use correct list variable.

CRs-Fixed: 2002748
Change-Id: Ibff56477ed3fba90c8ff704ea7dbe3c472f59836
Signed-off-by: Vatsal Bucha <vbucha@codeaurora.org>