ARM: dts: msm: Increase the snapshot size in device tree

Increase the size of snapshot static region to 1MB in the
device tree file for a5x targets which have preemption enabled.
This increase is needed to accommodate preemption records and
preemption history records. This overrides the snapshot size
specified in the driver code.

CRs-Fixed: 999360
Change-Id: I2cd27481cc0fb189e35ea44709fe27ad0884fcfd
Signed-off-by: Harshdeep Dhatt <hdhatt@codeaurora.org>