drm: tilcdc: use vblank hooks in struct drm_crtc_funcs

The vblank hooks in struct drm_driver are deprecated and only meant for
legacy drivers.  For modern drivers with DRIVER_MODESET flag, the hooks
in struct drm_crtc_funcs should be used instead.

While at it, the 'return' of .disable_vblank is dropped to fix the
following checkpatch warning.

 WARNING: void function return statements are not generally useful

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Cc: Jyri Sarha <jsarha@ti.com>
Acked-by: Jyri Sarha <jsarha@ti.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1486458995-31018-22-git-send-email-shawnguo@kernel.org

drivers/gpu/drm/tilcdc/tilcdc_crtc.c

@@ -695,6 +695,15 @@ static int tilcdc_crtc_atomic_check(struct drm_crtc *crtc,
 	return 0;
 }
 
+static int tilcdc_crtc_enable_vblank(struct drm_crtc *crtc)
+{
+	return 0;
+}
+
+static void tilcdc_crtc_disable_vblank(struct drm_crtc *crtc)
+{
+}
+
 static const struct drm_crtc_funcs tilcdc_crtc_funcs = {
 	.destroy        = tilcdc_crtc_destroy,
 	.set_config     = drm_atomic_helper_set_config,
@@ -702,6 +711,8 @@ static const struct drm_crtc_funcs tilcdc_crtc_funcs = {
 	.reset		= drm_atomic_helper_crtc_reset,
 	.atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
 	.atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
+	.enable_vblank	= tilcdc_crtc_enable_vblank,
+	.disable_vblank	= tilcdc_crtc_disable_vblank,
 };
 
 static const struct drm_crtc_helper_funcs tilcdc_crtc_helper_funcs = {

drivers/gpu/drm/tilcdc/tilcdc_drv.c

@@ -437,16 +437,6 @@ static irqreturn_t tilcdc_irq(int irq, void *arg)
 	return tilcdc_crtc_irq(priv->crtc);
 }
 
-static int tilcdc_enable_vblank(struct drm_device *dev, unsigned int pipe)
-{
-	return 0;
-}
-
-static void tilcdc_disable_vblank(struct drm_device *dev, unsigned int pipe)
-{
-	return;
-}
-
 #if defined(CONFIG_DEBUG_FS)
 static const struct {
 	const char *name;
@@ -557,8 +547,6 @@ static struct drm_driver tilcdc_driver = {
 			       DRIVER_PRIME | DRIVER_ATOMIC),
 	.lastclose          = tilcdc_lastclose,
 	.irq_handler        = tilcdc_irq,
-	.enable_vblank      = tilcdc_enable_vblank,
-	.disable_vblank     = tilcdc_disable_vblank,
 	.gem_free_object_unlocked = drm_gem_cma_free_object,
 	.gem_vm_ops         = &drm_gem_cma_vm_ops,
 	.dumb_create        = drm_gem_cma_dumb_create,