msm: modem-8960: Check if the modem is alive after restarting it

The modem is expected to enable its watchdog shortly after
it is booted up. Wait for 10 seconds after powering up
the modem and check if the modem watchdog has been enabled.
If not, restart the modem.

Change-Id: Iaeb2cb016a7a104f3370d8d589ff59c31c1fb1c8
Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>