drm/i915: Plop vlv/chv fifo sizes into crtc state

Move the vlv/chv FIFO size tracking into the crtc_state. As with the wms
for now this just acts as temporary storage.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170302171508.1666-6-ville.syrjala@linux.intel.com