drm: Drop unused forward declaration of drm_version

Signed-off-by: NGabriel Krisman Bertazi <krisman@collabora.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20161228143216.26821-4-krisman@collabora.co.uk

drivers/gpu/drm/drm_ioctl.c

@@ -95,9 +95,6 @@
  * broken.
  */
 
-static int drm_version(struct drm_device *dev, void *data,
-		       struct drm_file *file_priv);
-
 /*
  * Get the bus id.
  *