ARM: dts: msm: Add GPU support for MSM8917

Add device node for MSM8917 GPU and its properties.
It is needed to support graphics driver which is
accessed by various clients.

Change-Id: I831aa199d023f23261d24d687472fb63e5478160
Signed-off-by: Raghavendra Ambadas <rambad@codeaurora.org>