drm/i915: Store struct intel_crtc * in {pipe,plane}_to_crtc_mapping[]

A lot of users of the {pipe,plane}_to_crtc_mapping[] will end up
casting the result to intel_crtc, so let's just store the intel_crtc
pointer in the first place.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1477946245-14134-7-git-send-email-ville.syrjala@linux.intel.com
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
index 199b90c..81ed32b 100644
--- a/drivers/gpu/drm/i915/intel_lvds.c
+++ b/drivers/gpu/drm/i915/intel_lvds.c
@@ -985,7 +985,7 @@ void intel_lvds_init(struct drm_device *dev)
 	struct drm_display_mode *fixed_mode = NULL;
 	struct drm_display_mode *downclock_mode = NULL;
 	struct edid *edid;
-	struct drm_crtc *crtc;
+	struct intel_crtc *crtc;
 	i915_reg_t lvds_reg;
 	u32 lvds;
 	int pipe;
@@ -1166,7 +1166,7 @@ void intel_lvds_init(struct drm_device *dev)
 	crtc = intel_get_crtc_for_pipe(dev, pipe);
 
 	if (crtc && (lvds & LVDS_PORT_EN)) {
-		fixed_mode = intel_crtc_mode_get(dev, crtc);
+		fixed_mode = intel_crtc_mode_get(dev, &crtc->base);
 		if (fixed_mode) {
 			DRM_DEBUG_KMS("using current (BIOS) mode: ");
 			drm_mode_debug_printmodeline(fixed_mode);