msm: kgsl: Establish a standard GPU ID scheme for the KGSL core

Establish a standard generic format for a GPU ID in the KGSL core:

[0:15] - GPU specific identifier
[16:31] - 0x0002 for 2D or 0x0003 for 3D

Add a KGSL core function to get the GPU ID from the devices and
GPU specific functions to return them.  For Z180, the ID will be
0x0002000B4 (0xB4 = 180).  For 3D, the ID will be 0x00030000 ORed
with the GPU identifier (anywhere from 205 to 225).

Change-Id: Ic0dedbadddb3f587121913b9c226e2bda466f84e
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>