ARM: dts: msm: Disable msm-watchdog in SDM845 RUMI

Current msm-watchdog driver implementation relies on clocking scheme
that SDM845 RUMI does not following which leads to an infinite loop
when petting the watchdog.

Change-Id: Ic83265f6ed34a87e0655548aa64c659125298465
Signed-off-by: Kyle Yan <kyan@codeaurora.org>