drm/i915: properly check for MODESET for kms driver ioctls

Also ditch the cargo-culted dev_priv checks - either we have a
giant hole in our setup code or this is useless. Plainly bogus
to check for it in either case.

v2: Chris Wilson noticed that I've missed one bogus dev_priv check.

v3: The check in the overlay code is redundant (Chris)

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_sprite.c b/drivers/gpu/drm/i915/intel_sprite.c
index 4431567..2a20fb0 100644
--- a/drivers/gpu/drm/i915/intel_sprite.c
+++ b/drivers/gpu/drm/i915/intel_sprite.c
@@ -558,14 +558,13 @@
 			      struct drm_file *file_priv)
 {
 	struct drm_intel_sprite_colorkey *set = data;
-	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct drm_mode_object *obj;
 	struct drm_plane *plane;
 	struct intel_plane *intel_plane;
 	int ret = 0;
 
-	if (!dev_priv)
-		return -EINVAL;
+	if (!drm_core_check_feature(dev, DRIVER_MODESET))
+		return -ENODEV;
 
 	/* Make sure we don't try to enable both src & dest simultaneously */
 	if ((set->flags & (I915_SET_COLORKEY_DESTINATION | I915_SET_COLORKEY_SOURCE)) == (I915_SET_COLORKEY_DESTINATION | I915_SET_COLORKEY_SOURCE))
@@ -592,14 +591,13 @@
 			      struct drm_file *file_priv)
 {
 	struct drm_intel_sprite_colorkey *get = data;
-	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct drm_mode_object *obj;
 	struct drm_plane *plane;
 	struct intel_plane *intel_plane;
 	int ret = 0;
 
-	if (!dev_priv)
-		return -EINVAL;
+	if (!drm_core_check_feature(dev, DRIVER_MODESET))
+		return -ENODEV;
 
 	mutex_lock(&dev->mode_config.mutex);