radv: add the DGC preprocess BO to the cmdbuf BO list

This wasn't needed in practice because DGC NV is only enabled for
vkd3d-proton and it always uses the global BO list but better to add it
anyways.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29600>

src/amd/vulkan/radv_cmd_buffer.c

@@ -11591,6 +11591,8 @@ radv_CmdExecuteGeneratedCommandsNV(VkCommandBuffer commandBuffer, VkBool32 isPre
       radeon_emit(cmd_buffer->cs, 0);
    }
 
+   radv_cs_add_buffer(device->ws, cmd_buffer->cs, prep_buffer->bo);
+
    if (compute || !view_mask) {
       device->ws->cs_execute_ib(cmd_buffer->cs, ib_bo, ib_offset, cmdbuf_size >> 2, cmd_buffer->state.predicating);
    } else {