ARM: dts: msm: Correct the pet time NS WDOG on msm8953

Timer inaccuracy is within 640ms, so pet time should
be 10s - 640ms = 9360ms.

Change-Id: I625b2c04668926728ad73d7d034db7f32db9e3f5
Signed-off-by: Maria Yu <aiquny@codeaurora.org>