Add support for running wic images with EFI as testimage.
Introduces a variable called QEMU_USE_OVMF for configuration.
(From OE-Core rev: 3af8aaff68ed332d812ea7dc184d392700ad7882)
Signed-off-by: Konrad Weihmann <kweihmann@outlook.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>