msm: Add support for watchdog on msm8974

In case of a watchdog bark time out, dump
the cpu alive mask and last pet time, to determine cpu
hangs or deadlock scenarios as cause of the timeout.
In case of a kernel panic, adjust bark and bite
timeouts based on panic timeout, to allow for completion
of panic handling prior to watchdog bark or bite.

Change-Id: I4401db681cbad54abb0f14ae84550fc63663fb04
Signed-off-by: Hanumant Singh <hanumant@codeaurora.org>