drm: WARN() when drm_connector_attach_property fails

Also return void instead of int. We have more than 100 callers and
no one checks for the return value.

If this function fails the property won't be exposed by the get/set
ioctls, but we should probably survive. If this starts happening,
the solution will be to increase DRM_CONNECTOR_MAX_PROPERTY and
recompile the Kernel.

Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Rob Clark <rob.clark@linaro.org>
Tested-by: Rob Clark <rob.clark@linaro.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index f35e7ed..036faec 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -910,8 +910,8 @@
 extern void drm_crtc_probe_connector_modes(struct drm_device *dev, int maxX, int maxY);
 extern bool drm_crtc_in_use(struct drm_crtc *crtc);
 
-extern int drm_connector_attach_property(struct drm_connector *connector,
-				      struct drm_property *property, uint64_t init_val);
+extern void drm_connector_attach_property(struct drm_connector *connector,
+					  struct drm_property *property, uint64_t init_val);
 extern struct drm_property *drm_property_create(struct drm_device *dev, int flags,
 						const char *name, int num_values);
 extern struct drm_property *drm_property_create_enum(struct drm_device *dev, int flags,