drm/nouveau/bus/tu104: initial support

Appears to be compatible with GF100.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

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

@@ -2438,6 +2438,7 @@ static const struct nvkm_device_chip
 nv164_chipset = {
 	.name = "TU104",
 	.bios = nvkm_bios_new,
+	.bus = gf100_bus_new,
 	.devinit = tu104_devinit_new,
 	.fuse = gm107_fuse_new,
 	.gpio = gk104_gpio_new,