xwayland: Propagate damage x1/y1 coordinates in xwl_present_flip
This couldn't have worked correctly for non-0 x1/y1.
Noticed by inspection.
Reviewed-by: 
Simon Ser <contact@emersion.fr>
This couldn't have worked correctly for non-0 x1/y1.
Noticed by inspection.
Reviewed-by: Simon Ser <contact@emersion.fr>