Revert "drm/virtio: fix DRM_FORMAT_* handling"

This reverts commit 42fd9e6c.

This restores the standard pixel formats that Android requires of all
GPU implementations.

BUG: 139386555
Change-Id: Ie6e33501c9d9e308a2636547ad3cd9a210d011bd
Test: Booted local build of master with -gpu_mode=drm_virgl
Signed-off-by: Greg Hartman <ghartman@google.com>