drm: Enable drm drivers to add drm sysfs devices.

Export utility functions for drivers to add specialized devices in the
sysfs drm class subdirectory.

Initially this will be needed form TTM to add a virtual device that
handles power management.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@linux.ie>

include/drm/drm_sysfs.h

@@ -0,0 +1,12 @@
+#ifndef _DRM_SYSFS_H_
+#define _DRM_SYSFS_H_
+
+/**
+ * This minimalistic include file is intended for users (read TTM) that
+ * don't want to include the full drmP.h file.
+ */
+
+extern int drm_class_device_register(struct device *dev);
+extern void drm_class_device_unregister(struct device *dev);
+
+#endif