msm: kgsl: Add support to get gpu model from device tree

We would have different gpu model name for different hardware
specification. Add support to get gpu model properties from
device tree against gpu hardware configuration.

Change-Id: I85c4e1b1354ed63713535d5f01f6633138516de7
Signed-off-by: Hareesh Gundu <hareeshg@codeaurora.org>