Add mention to new tree for the nova driver development

This was introduced by Danilo Krummich in
https://lore.kernel.org/all/20250901202850.208116-1-dakr@kernel.org/

Author: CastilloDel

src/Nova-GPU-Driver.md

@@ -21,8 +21,10 @@ Available communication channels are:
 The parts that are already in mainline Linux can be found in
 `drivers/gpu/nova-core/` and `drivers/gpu/drm/nova/`
 
-The development repository for the in-tree driver is located on
-[Freedesktop](https://gitlab.freedesktop.org/drm/nova).
+[This Freedesktop repository](https://gitlab.freedesktop.org/drm/nova) was
+made to host the in-tree driver for Nova. However, development currently
+takes place in [the drm-rust-next tree](https://gitlab.freedesktop.org/drm/rust/kernel/-/tree/drm-rust-next)
+alongside other DRM Rust drivers, for easier collaboration and integration.
 
 
 ## Background