drm/nouveau/gr/gf100-: fix wrong constant definition

Commit 3740c825 ("drm/nouveau/gr/gf100-: add symbolic names for
classes") introduced a wrong macro definition causing acceleration setup
to fail. Fix it.

Signed-off-by: Lars Seipel <ls@slrz.net>
Fixes: 3740c825 ("drm/nouveau/gr/gf100-: add symbolic names for classes")
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>