drm/nouveau: assign fence_chan->name correctly

Make nouveau_fence_chan refcounted, to make trace_fence_destroy
always return the correct name without a race condition.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>

diff --cc drivers/gpu/drm/nouveau/nouveau_fence.c
Simple merge

diff --cc drivers/gpu/drm/nouveau/nouveau_fence.h
Simple merge

diff --cc drivers/gpu/drm/nouveau/nv04_fence.c
Simple merge

diff --cc drivers/gpu/drm/nouveau/nv10_fence.c
Simple merge

diff --cc drivers/gpu/drm/nouveau/nv84_fence.c
Simple merge