Otherwise DRM_CAP_DUMB_PREFERRED_DEPTH is zero.
Signed-off-by: Simon Ser <contact@emersion.fr>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/o2SmEP0M6h287Fs5OeL3HtQzTr8uV0PyOhFict_qdxeS7vFvV1Zr8qzRUJh-YnCoJHo13nJgAqqQByzEzTZTqk9R2ExsOszYLj68hQLqBIc=@emersion.fr