ARM: dts: msm: Increase GPU snapshot size for sdmmagpie

Currently snapshot binary is missing some needed data
due to less snapshot size. So increase GPU snapshot size
to 2MB to get all needed data in snapshot binary.

Change-Id: I9e1c484a07f25e446616f30fd686b4ed872cffef
Signed-off-by: Hareesh Gundu <hareeshg@codeaurora.org>