drm/nouveau: use MSI interrupts

MSIs were only problematic on some old, broken chipsets. But now that we
already see systems where PCI legacy interrupts are somewhat flaky, it's
really time to move to MSIs.

v2 (Ben Skeggs): blacklist BR02 boards

Signed-off-by: Lucas Stach <dev@lynxeye.de>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>