virtual/gl may not necessarily be mesa, and virgl needs
specifically the gbm part of mesa.
There's also hope nvidia will support gbm somehow, someday.
(From OE-Core rev: fd807dfa2ec25111dd359ec87d197020e747cf0d)
Signed-off-by: Alexander Kanavin <alex.kanavin@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>