soc: qcom: Change to new timer API for watchdog driver.

init_timer* APIs are no longer available in upstream kernel. Change
the watchdog driver code to use newer APIs.

Change-Id: Ie6c617dcc67f063a91494b2d0ebf066a9306eaaa
Signed-off-by: Rishabh Bhatnagar <rishabhb@codeaurora.org>