virtgpu_virgl: properly resolve flexible formats

DRM_FORMAT_FLEX_YCbCr_420_888 gets the fallthrough but
DRM_FORMAT_FLEX_IMPLEMENTATION_DEFINED is missed. This change updates to
resolve flexible format into explicit format first and then further
resolve explicit format in a 2nd pass.

BUG=b:260032660
TEST=cts

Change-Id: I69724f5845299a79a315ab32ddf5a207cdfa26b6
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/minigbm/+/4133686
Tested-by: Yiwei Zhang <zzyiwei@chromium.org>
Reviewed-by: Ryan Neph <ryanneph@google.com>
Commit-Queue: Yiwei Zhang <zzyiwei@chromium.org>
1 file changed