ARM: dts: msm: Add MSM8992 GPU device tree file

Define device specific GPU properties for MSM8992 such as ChipID,
register mappings, interrupts, clocks, buses, IOMMU and power
level settings.

Change-Id: I715797ead2e3b3fcbef5ac6a60577f43a0c704d1
Signed-off-by: Lokesh Batra <lbatra@codeaurora.org>