drm/nouveau: initial pass at moving to struct nvif_device

This is an attempt at isolating some of the changes necessary to port
to NVIF in a separate commit.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nv10_fence.c

@@ -53,7 +53,7 @@ nv10_fence_sync(struct nouveau_fence *fence,
 u32
 nv10_fence_read(struct nouveau_channel *chan)
 {
-	return nv_ro32(chan->object, 0x0048);
+	return nvif_rd32(chan, 0x0048);
 }
 
 void