drm/i915: Check infoframe state more diligently.

Check that the DIP is enabled on the right port on IBX and VLV/CHV as
we're doing on g4x, and also check for all the infoframe enable bits on
all platforms.

Eventually we should track each infoframe type independently, and also
their contents. This is a small step in that direction as .infoframe_enabled()
return value could be easily turned into a bitmask.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Chandra Konduru <Chandra.konduru@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>