libweston/linux-dmabuf: create surface feedback on demand

Unconditionally creating a surface feedback for each surface
creates unnecessary overhead and noise in the logs. Thus
create it when the first surface feedback resource for a
surface is requested and delete it again once all those
resources have been destroyed.

Signed-off-by: Robert Mader <robert.mader@collabora.com>
(cherry picked from commit 53a221cc)