drm: WARN when trying add enum values to non-enum/bitmask properties

Trying to add enum values to non-enum/bitmask properties is a
programmer mistake. WARN to make sure the developers notice
their mistake.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180306164849.2862-2-ville.syrjala@linux.intel.comReviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/drm_property.c

@@ -378,8 +378,8 @@ int drm_property_add_enum(struct drm_property *property, int index,
 	if (WARN_ON(strlen(name) >= DRM_PROP_NAME_LEN))
 		return -EINVAL;
 
-	if (!(drm_property_type_is(property, DRM_MODE_PROP_ENUM) ||
-			drm_property_type_is(property, DRM_MODE_PROP_BITMASK)))
+	if (WARN_ON(!drm_property_type_is(property, DRM_MODE_PROP_ENUM) &&
+		    !drm_property_type_is(property, DRM_MODE_PROP_BITMASK)))
 		return -EINVAL;
 
 	/*