drm/i915: Include fb modifier in state dumps

To help diagnose modifier related issues let's include that
information in the various state dumps.

Cc: Simon Ser <contact@emersion.fr>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201103153026.16566-1-ville.syrjala@linux.intel.com


Acked-by: Simon Ser <contact@emersion.fr>