Add 6-bit and 8-bit gradients for factory display test.

We used to only have 4-bit gradients (16 colors).  Now a single
screen shows 3 different gradients: 16-color, 64-color, and 256-color.

BUG=none
TEST=Ran on device and saw 3 different gradients.

Change-Id: I45d7f734a605c6c2c849cae53b99ab308173c274
Reviewed-on: http://gerrit.chromium.org/gerrit/1457
Tested-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Nick Sanders <nsanders@chromium.org>
1 file changed