drm/nouveau/i2c/gk110b,gm10x: use the correct implementation

DPAUX registers moved on Kepler, these chipsets were still using the
Fermi implementation for some reason.

This fixes detection of hotplug/sink IRQs on DP connectors.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Cc: stable@vger.kernel.org