When we don't have a real device/image path, such as 'bootefi hello',
construct a mem-mapped device-path.
This fixes 'bootefi hello' after devicepath refactoring.
Fixes: bd8b73b88f ("efi_loader: refactor boot device and loaded_image handling") Signed-off-by: Rob Clark <robdclark@gmail.com> Acked-by: Heinrich Schuchardt <xypron.glpk@gmx.de> Signed-off-by: Alexander Graf <agraf@suse.de>