drm/nouveau/fifo/tu106: initial support

Appears to be compatible with TU104.
Signed-off-by: NBen Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nvkm/engine/device/base.c

@@ -2490,6 +2490,7 @@ nv166_chipset = {
 	.top = gk104_top_new,
 	.disp = tu104_disp_new,
 	.dma = gv100_dma_new,
+	.fifo = tu104_fifo_new,
 };
 
 static int