msm: kgsl: Move the secure region to 0xE8000000

We can only have one secure region to rule them all and since legacy
and 32 bit applications need to have access to the region too, we
need to move it into the lower 32 bits.

Change-Id: Ic0dedbada6de060b2ac3d0c26e9ea91a833a16f8
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>