soc: qcom: watchdog_v2: add support to enable watchdog feature

Currently we disable Non secure watchdog during suspend and
re-enable it during resume. This leaves suspend / resume path
unprotected by Non secure watchdog. There is a feature in
hardware where watchdog freezes automatically when all online
cores are in suspend and unfreezes watchdog upon wakeup event
from low power mode. Set the bit in watchdog control register to
enable this feature and protect suspend / resume path by Non
secure watchdog.

Change-Id: Ibca425a661c74bd1d46513783780ea213a51f87f
Signed-off-by: Sarangdhar Joshi <spjoshi@codeaurora.org>