drm/i915/fbc: s/parms/fbc_state/

Rename the 'params' to just fbc state.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211124113652.22090-19-ville.syrjala@linux.intel.com


Reviewed-by: Mika Kahola <mika.kahola@intel.com>