drm/nouveau/disp/nv50-: specify ctrl/user separately when constructing classes

[ Upstream commit 2a32b9b1866a2ee9f01fbf2a48d99012f0120739 ]

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>