drm/i915: Fix Haswell/CRW PCI IDs.

The second digit was off by one, which meant we accidentally treated
GT(n) as GT(n-1).  This also meant no support for GT1 at all.

Cc: stable@kernel.org
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>