linux-dmabuf: disable fine-grained feedback again

Despite the better debouncing in wlroots 0.19, this is still causing
problems. In particular, certain clients (mostly Xwayland games it
seems) have a bad interaction with this additional feedback, possibly
related to the cursor buffer.

The reported symptoms are significant framerate drops and stuttering on
pointer input.

Probably there's a wlroots bug here at fault but I don't have the
resources to fix it myself currently and would rather not force river
users to suffer.

Setting WLR_SCENE_DISABLE_DIRECT_SCANOUT=1 isn't sufficient to solve
these problems either, as wlr_scene still sends enough extra feedback
to trigger the problems.

Closes: https://codeberg.org/river/river/issues/1277

river/Root.zig

@@ -124,8 +124,6 @@ pub fn init(root: *Root) !void {
     const gamma_control_manager = try wlr.GammaControlManagerV1.create(server.wl_server);
     scene.setGammaControlManagerV1(gamma_control_manager);
 
-    if (server.linux_dmabuf) |linux_dmabuf| scene.setLinuxDmabufV1(linux_dmabuf);
-
     const interactive_content = try scene.tree.createSceneTree();
     const drag_icons = try scene.tree.createSceneTree();
     const hidden_tree = try scene.tree.createSceneTree();