ui/gtk: fix passing y0_top parameter to scanout

The dmabuf->y0_top flag is passed to .dpy_gl_scanout_dmabuf(), however
in the gtk ui both implementations dropped it when doing the next
scanout_texture call.

Fixes flipped linux console using vhost-user-gpu with the gtk ui
display.

Signed-off-by: Erico Nunes <ernunes@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20230220175605.43759-1-ernunes@redhat.com>

ui/gtk-egl.c

@@ -256,7 +256,7 @@ void gd_egl_scanout_dmabuf(DisplayChangeListener *dcl,
     }
 
     gd_egl_scanout_texture(dcl, dmabuf->texture,
-                           false, dmabuf->width, dmabuf->height,
+                           dmabuf->y0_top, dmabuf->width, dmabuf->height,
                            0, 0, dmabuf->width, dmabuf->height);
 
     if (dmabuf->allow_fences) {

ui/gtk-gl-area.c

@@ -298,7 +298,7 @@ void gd_gl_area_scanout_dmabuf(DisplayChangeListener *dcl,
     }
 
     gd_gl_area_scanout_texture(dcl, dmabuf->texture,
-                               false, dmabuf->width, dmabuf->height,
+                               dmabuf->y0_top, dmabuf->width, dmabuf->height,
                                0, 0, dmabuf->width, dmabuf->height);
 
     if (dmabuf->allow_fences) {