soc: qcom: Disable Blackghost interrupts before MSM is shutdown

During system reboot, SSR signal from BG delays reboot of MSM.
Disable Blackghost interrupt to avoid this.

Change-Id: I874f033dc318b8653015bc909527411cf3645b7f
Signed-off-by: Avaneesh Kumar Dwivedi <akdwived@codeaurora.org>