add 24bpp support

Now that cirrusdrmfb is enabled in QEMU /dev/fb0 exists
and ply-image runs and fails. Cirrus VGA has 24bpp pixels and
ply-image so far only supported 16bpp and 32bpp. This commit
adds support for 24bpp framebuffers. It also adds cirrus
device to KMS list.

BUG=chromium:289439
TEST=run smoke test

Change-Id: I0115021a17ce39c29316d453ab52a705084268e8
Signed-off-by: Dominik Behr <dbehr@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/169016
Reviewed-by: St├ęphane Marchesin <marcheu@chromium.org>
2 files changed