crtc->config is updated to always contain to the active crtc_state
and only differs from crtc_state during crtc_disable. It will
eventually be removed, so start with some low hanging fruit.

For crtc->active the situation is the same; it will be removed
eventually. Instead use crtc->state->active.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: NMatt Roper <matthew.d.roper@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>