soc: qcom: ssr: Force shutdown of modem during adb reboot

Modem may need to do certain housekeeping during user initiated
reboot, hence invoke modem force shutdown during system reboot.

Change-Id: I1fc53b4bc32a9ef172b9e87fc41c73c990a7c6b4
Signed-off-by: Avaneesh Kumar Dwivedi <akdwived@codeaurora.org>