msm: kgsl: Map ebi memory to kernel

Implement the function to map ebi memory to the kernel.
This function is used when from postmortem or snapshot
when there is a hang and we are allocating memory from
kernel ebi space

Change-Id: I4f3e8b3fcb8c0107599ce3d3636c0ed33ace725a
Signed-off-by: Shubhraprakash Das <sadas@codeaurora.org>