virtgpu: set blob_id when creating blob resources

virtgpu: set blob_id when creating blob resources

Setting the blob_id is necessary to prevent a race where the cmds for
two concurrent CREATE_BLOB ioctls get swapped.

BUG=b:170375809
TEST=android.media.cts.EncoderTest

Change-Id: I74d4ebe9a819f0564e10736ba5f35c5f8fc8aa1b
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/minigbm/+/2503995
Reviewed-by: Jason Macnak <natsu@google.com>
Reviewed-by: Gurchetan Singh <gurchetansingh@chromium.org>
Commit-Queue: David Stevens <stevensd@chromium.org>
Tested-by: David Stevens <stevensd@chromium.org>