v3dv: don't leak prog_data from shader variants

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6766>

src/broadcom/vulkan/v3dv_pipeline.c

@@ -99,6 +99,7 @@ destroy_pipeline_stage(struct v3dv_device *device,
 
       if (variant->assembly_bo) {
          v3dv_bo_free(device, variant->assembly_bo);
+         ralloc_free(variant->prog_data.base);
          vk_free2(&device->alloc, pAllocator, variant);
       }
    }