zoom: fix zoom

Right now zoom only works on the output at 0, 0 because it's adding
the output corner co-ordinates to global co-ordinates that already
include the output offset.

Signed-off-by: Derek Foreman <derekf@osg.samsung.com>
Reviewed-by: Bryce Harrington <b.harrington@samsung.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
1 file changed