Like the rest of the intel atomic functions we should pass along
intel_crtc_state, and dereference drm_crtc_state only through
intel_crtc_state->base

While at it, rename old/new_state to old/new_crtc_state. (Ville)
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/20190628085517.31886-4-maarten.lankhorst@linux.intel.com