drm/i915: Rename struct intel_crtc_config to intel_crtc_state

The objective is to make this structure usable with the atomic helpers,
so let's start with the rename. Patch generated with coccinelle:

@@ @@
-struct intel_crtc_config {
+struct intel_crtc_state {
...
}
@@ @@
-struct intel_crtc_config
+struct intel_crtc_state

v2: Completely generate the patch with cocci. (Ander)

Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>