drm/i915: Pass crtc_state to ivybridge_update_fdi_bc_bifurcation

We have to look at crtc_state, so pass that instead.
Also cleanup the use of dev vs dev_priv, we really want to pass along
dev_priv.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181011100457.8776-10-maarten.lankhorst@linux.intel.com