CHROMIUM: config: Built-in PowerVR driver 1.7 and 1.8 as module

In preparation for the transition from UM 1.7 to 1.8, configure KM
1.7 as built-in, and KM 1.8 as module.

This allows UM 1.8 to unbind KM 1.8, then load and bind KM 1.7.

BUG=b:37234148
TEST=Boot to UI on Elm

Change-Id: I6cacce151bec22b1dacc2449e28847016e340a87
Signed-off-by: Frank Binns <frank.binns@imgtec.com>
Reviewed-on: https://chromium-review.googlesource.com/486721
Commit-Ready: Nicolas Boichat <drinkcat@chromium.org>
Tested-by: Nicolas Boichat <drinkcat@chromium.org>
Reviewed-by: Nicolas Boichat <drinkcat@chromium.org>
6 files changed