minigbm: tegra: add blocklinear detiling logic

minigbm: tegra: add blocklinear detiling logic

With CL:397941, hshi@ figured out how to detile blocklinear buffers
for tegra. Let's add that logic to our tegra map()/unmap() functions.
This can be useful for various tests.

BUG=chromium:673570
TEST=tiled_bo_test draws ellipse texture on Tegra (there are artifacts
     due another bug though)

Change-Id: I7c2e7222ba67457ffd3641ba42a775ac4a667ec8
Reviewed-on: https://chromium-review.googlesource.com/421279
Commit-Ready: Gurchetan Singh <gurchetansingh@chromium.org>
Tested-by: Gurchetan Singh <gurchetansingh@chromium.org>
Reviewed-by: Haixia Shi <hshi@chromium.org>