ARM: dts: msm: Update the pet time NS WDOG on sdm845

As per the timer code on 4.9 kernel the granularity for timer with
10 second expiry is 640ms. So if the NS wdog timer expiry is 10 the
worst case expiry for 10.64 seconds. Due the timer in accuracy there
could be false NS Wdog barks as this reduces time between pet and bark.
Update the pet time to account for the inaccuracy.

Change-Id: I7e3b8f2ce3696515922ca58e64028d97381e4899
Signed-off-by: Channagoud Kadabi <ckadabi@codeaurora.org>