ARM: dts: msm: update splash buffer address for msm8996

Update splash buffer address and size for msm8996 to
avoid overlap with ramdisk image and accommodate high
resolution splash images.

Change-Id: I570a2579909f0ad772f3e8937e6cd7b963174d81
Signed-off-by: Dhaval Patel <pdhaval@codeaurora.org>