xfree86: vgaarb: close and cleanup vga arbiter

So far there are no apparently issues on not closing the fd. But let's do the
right job here.

Signed-off-by: Tiago Vignatti <tiago.vignatti@nokia.com>
Acked-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

hw/xfree86/common/xf86Init.c

@@ -1181,6 +1181,8 @@ ddxGiveUp(void)
 {
     int i;
 
+    xf86VGAarbiterFini();
+
 #ifdef XF86PM
     if (xf86OSPMClose)
 	xf86OSPMClose();