ARM: dts: msm: Enable watchdog timer for flash LED

Flash LED raises module temperature when turned on. Long time
leaving on flash LED has risk to damage hardware due to thermal
condition. Enabling watchdog timer for flash LED torch mode to
let hardware turn off flash LEDs at perdefined duration.

CRs-Fixed: 514534
Change-Id: I6e65da0ae517fedcd44810ec3f984a73c1c9130f
Signed-off-by: Chun Zhang <chunz@codeaurora.org>