drm/i915: Initial command parser table definitions

Add command tables defining irregular length commands for each ring.
This requires a few new command opcode definitions.

v2: Whitespace adjustment in command definitions, sparse fix for !F

OTC-Tracker: AXIA-4631
Change-Id: I064bceb457e15f46928058352afe76d918c58ef5
Signed-off-by: Brad Volkin <bradley.d.volkin@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>