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-ark-0.7.5/src/ark_driver.c.~1~	2012-07-17 00:51:36.000000000 -0400
+++ xf86-video-ark-0.7.5/src/ark_driver.c	2014-12-19 00:23:13.028931734 -0500
@@ -39,7 +39,6 @@
 #include "compiler.h"
 #include "mipointer.h"
 #include "micmap.h"
-#include "mibstore.h"
 #include "fb.h"
 #include "ark.h"
 
@@ -538,7 +537,6 @@
 
 	fbPictureInit (pScreen, 0, 0);
 
-	miInitializeBackingStore(pScreen);
 	xf86SetBackingStore(pScreen);
 
 	if (!pARK->NoAccel) {