aco/ngg: Create LDS layout for NGG GS.

For NGG GS, we need to store the following in LDS:

1. The ESGS ring, similarly to legacy ESGS.
2. Emitted vertices from the GS threads.
3. Temporary space used by the workgroup scan.

Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
Reviewed-by: Rhys Perry <pendingchaos02@gmail.com>
Part-of: <mesa/mesa!6964>