msm: pil-q6v5-lpass: Remove disabling watchdog irq multiple times

Disabling watchdog irq twice requires enabling it an equal number
of times. Due to the watchdog irq being disabled twice while being
enabled only once; on watchdog bite happening muliple times, the
watchdog handler is not fired for the subsequent ones.

This change makes sure that this is rectified by disabling the
irq only once when the subsystem is shutdown during restart.

Change-Id: I58732e6a6d3d484bed53dc8198e8794eefd1b45c
Signed-off-by: Deepak Katragadda <dkatraga@codeaurora.org>