drm/i915: add crtc->enable/disable vfuncs insted of dpms

Because that's what we're essentially calling. This is the first step
in untangling the crtc_helper induced dpms handling mess we have - at
the crtc level we only have 2 states and the magic is just in
selecting which one (and atm there isn't even much magic, but on
recent platforms where not even the crt output has more than 2 states
we could do better).

Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index ed3ba70..fb46c6f 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -240,7 +240,6 @@
 };
 
 struct drm_i915_display_funcs {
-	void (*dpms)(struct drm_crtc *crtc, int mode);
 	bool (*fbc_enabled)(struct drm_device *dev);
 	void (*enable_fbc)(struct drm_crtc *crtc, unsigned long interval);
 	void (*disable_fbc)(struct drm_device *dev);
@@ -256,6 +255,8 @@
 			     struct drm_display_mode *adjusted_mode,
 			     int x, int y,
 			     struct drm_framebuffer *old_fb);
+	void (*crtc_enable)(struct drm_crtc *crtc);
+	void (*crtc_disable)(struct drm_crtc *crtc);
 	void (*off)(struct drm_crtc *crtc);
 	void (*write_eld)(struct drm_connector *connector,
 			  struct drm_crtc *crtc);