drm/i915: Fix command parser table validator

As we may like to use a bisection search on the tables in future, we
need them to be ordered. For convenience we expect the compiled tables
to be order and check on initialisation. However, the validator used the
wrong iterators failed to spot the misordered MI tables and instead
walked off into the unknown (as spotted by kasan).

Signed-off-by: Hanno Boeck <hanno@hboeck.de>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
[danvet: Again hand-assemble patch ...]
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>