ARM: dts: msm: Update GPU fmax for atoll

Atoll GPU can support max clock up to 825Mhz.
Update GPU max frequency as per requirement.

Change-Id: I514430ca1e912628c88738ed5333d9e23a59b1e7
Signed-off-by: Hareesh Gundu <hareeshg@codeaurora.org>