Now that the kselftest infrastructure exists, put it to use and add to
it the existing consistency checks on the fw register lookup tables.

v2: s/tabke/table/
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170213171558.20942-22-chris@chris-wilson.co.uk