Removes references to mibstore.h and miInitializeBackingStore, which
have been removed from xorg-server.  Zack Rusin <zackr@vmware.com>
wrote: "It was a noop for at least 5 years and it has been removed."
See: http://patches.openembedded.org/patch/46133/

--- xf86-video-tdfx-1.4.5/src/tdfx_driver.c.~1~	2012-07-17 01:21:16.000000000 -0400
+++ xf86-video-tdfx-1.4.5/src/tdfx_driver.c	2014-12-19 01:36:42.762798424 -0500
@@ -62,10 +62,6 @@
 
 #include "compiler.h"
 
-/* Drivers using the mi implementation of backing store need: */
-
-#include "mibstore.h"
-
 /* All drivers using the vgahw module need this */
 /* This driver needs to be modified to not use vgaHW for multihead operation */
 #include "vgaHW.h"
@@ -2373,7 +2369,6 @@
     }
   }
 
-  miInitializeBackingStore(pScreen);
   xf86SetBackingStore(pScreen);
   xf86SetSilkenMouse(pScreen);
 
