msm: kgsl: Map GPU QDSS STM through GPU IOMMU

Map the GPU QDSS STM area as a global into the GPU
IOMMU so that GPU traces can be routed to QDSS.
Enable the gpuaddr and size of the area to be queried
from userspace.

CRs-Fixed: 1031648
Change-Id: I2e32522a42508a6bee088c95dc56a13935dd691c
Signed-off-by: Jonathan Wicks <jwicks@codeaurora.org>