ARM: dts: msm: add apps watchdog entry for msmferrum

Add watchdog entry to device tree to enable configuring
the watchdog timer to cause barks and bites so as to detect
system hangs.

Change-Id: I250456ab68d48df9f50126e69d88152e654a6d5d
Signed-off-by: Xiaogang Cui <xiaogang@codeaurora.org>