drm/nouveau: initialise display before enabling interrupts

In some situations it's possible we can receive a spurious hotplug IRQ
before we're ready to handle it, leading to an oops.

Calling the display init before enabling interrupts should clear any
pending IRQs on the GPU and prevent this from happening.

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

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